The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/vfs/hammer/hammer_object.c

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    1 /*
    2  * Copyright (c) 2007-2008 The DragonFly Project.  All rights reserved.
    3  * 
    4  * This code is derived from software contributed to The DragonFly Project
    5  * by Matthew Dillon <dillon@backplane.com>
    6  * 
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in
   15  *    the documentation and/or other materials provided with the
   16  *    distribution.
   17  * 3. Neither the name of The DragonFly Project nor the names of its
   18  *    contributors may be used to endorse or promote products derived
   19  *    from this software without specific, prior written permission.
   20  * 
   21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
   25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
   27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  */
   34 
   35 #include "hammer.h"
   36 
   37 static int hammer_mem_lookup(hammer_cursor_t cursor);
   38 static void hammer_mem_first(hammer_cursor_t cursor);
   39 static int hammer_frontend_trunc_callback(hammer_record_t record,
   40                                 void *data __unused);
   41 static int hammer_bulk_scan_callback(hammer_record_t record, void *data);
   42 static int hammer_record_needs_overwrite_delete(hammer_record_t record);
   43 static int hammer_delete_general(hammer_cursor_t cursor, hammer_inode_t ip,
   44                                 hammer_btree_leaf_elm_t leaf);
   45 static int hammer_cursor_localize_data(hammer_data_ondisk_t data,
   46                                 hammer_btree_leaf_elm_t leaf);
   47 
   48 struct rec_trunc_info {
   49         u_int16_t       rec_type;
   50         int64_t         trunc_off;
   51 };
   52 
   53 struct hammer_bulk_info {
   54         hammer_record_t record;
   55         hammer_record_t conflict;
   56 };
   57 
   58 /*
   59  * Red-black tree support.  Comparison code for insertion.
   60  */
   61 static int
   62 hammer_rec_rb_compare(hammer_record_t rec1, hammer_record_t rec2)
   63 {
   64         if (rec1->leaf.base.rec_type < rec2->leaf.base.rec_type)
   65                 return(-1);
   66         if (rec1->leaf.base.rec_type > rec2->leaf.base.rec_type)
   67                 return(1);
   68 
   69         if (rec1->leaf.base.key < rec2->leaf.base.key)
   70                 return(-1);
   71         if (rec1->leaf.base.key > rec2->leaf.base.key)
   72                 return(1);
   73 
   74         /*
   75          * For search & insertion purposes records deleted by the
   76          * frontend or deleted/committed by the backend are silently
   77          * ignored.  Otherwise pipelined insertions will get messed
   78          * up.
   79          *
   80          * rec1 is greater then rec2 if rec1 is marked deleted.
   81          * rec1 is less then rec2 if rec2 is marked deleted.
   82          *
   83          * Multiple deleted records may be present, do not return 0
   84          * if both are marked deleted.
   85          */
   86         if (rec1->flags & (HAMMER_RECF_DELETED_FE | HAMMER_RECF_DELETED_BE |
   87                            HAMMER_RECF_COMMITTED)) {
   88                 return(1);
   89         }
   90         if (rec2->flags & (HAMMER_RECF_DELETED_FE | HAMMER_RECF_DELETED_BE |
   91                            HAMMER_RECF_COMMITTED)) {
   92                 return(-1);
   93         }
   94 
   95         return(0);
   96 }
   97 
   98 /*
   99  * Basic record comparison code similar to hammer_btree_cmp().
  100  *
  101  * obj_id is not compared and may not yet be assigned in the record.
  102  */
  103 static int
  104 hammer_rec_cmp(hammer_base_elm_t elm, hammer_record_t rec)
  105 {
  106         if (elm->rec_type < rec->leaf.base.rec_type)
  107                 return(-3);
  108         if (elm->rec_type > rec->leaf.base.rec_type)
  109                 return(3);
  110 
  111         if (elm->key < rec->leaf.base.key)
  112                 return(-2);
  113         if (elm->key > rec->leaf.base.key)
  114                 return(2);
  115 
  116         /*
  117          * Never match against an item deleted by the frontend
  118          * or backend, or committed by the backend.
  119          *
  120          * elm is less then rec if rec is marked deleted.
  121          */
  122         if (rec->flags & (HAMMER_RECF_DELETED_FE | HAMMER_RECF_DELETED_BE |
  123                           HAMMER_RECF_COMMITTED)) {
  124                 return(-1);
  125         }
  126         return(0);
  127 }
  128 
  129 /*
  130  * Ranged scan to locate overlapping record(s).  This is used by
  131  * hammer_ip_get_bulk() to locate an overlapping record.  We have
  132  * to use a ranged scan because the keys for data records with the
  133  * same file base offset can be different due to differing data_len's.
  134  *
  135  * NOTE: The base file offset of a data record is (key - data_len), not (key).
  136  */
  137 static int
  138 hammer_rec_overlap_cmp(hammer_record_t rec, void *data)
  139 {
  140         struct hammer_bulk_info *info = data;
  141         hammer_btree_leaf_elm_t leaf = &info->record->leaf;
  142 
  143         if (rec->leaf.base.rec_type < leaf->base.rec_type)
  144                 return(-3);
  145         if (rec->leaf.base.rec_type > leaf->base.rec_type)
  146                 return(3);
  147 
  148         /*
  149          * Overlap compare
  150          */
  151         if (leaf->base.rec_type == HAMMER_RECTYPE_DATA) {
  152                 /* rec_beg >= leaf_end */
  153                 if (rec->leaf.base.key - rec->leaf.data_len >= leaf->base.key)
  154                         return(2);
  155                 /* rec_end <= leaf_beg */
  156                 if (rec->leaf.base.key <= leaf->base.key - leaf->data_len)
  157                         return(-2);
  158         } else {
  159                 if (rec->leaf.base.key < leaf->base.key)
  160                         return(-2);
  161                 if (rec->leaf.base.key > leaf->base.key)
  162                         return(2);
  163         }
  164 
  165         /*
  166          * We have to return 0 at this point, even if DELETED_FE is set,
  167          * because returning anything else will cause the scan to ignore
  168          * one of the branches when we really want it to check both.
  169          */
  170         return(0);
  171 }
  172 
  173 /*
  174  * RB_SCAN comparison code for hammer_mem_first().  The argument order
  175  * is reversed so the comparison result has to be negated.  key_beg and
  176  * key_end are both range-inclusive.
  177  *
  178  * Localized deletions are not cached in-memory.
  179  */
  180 static
  181 int
  182 hammer_rec_scan_cmp(hammer_record_t rec, void *data)
  183 {
  184         hammer_cursor_t cursor = data;
  185         int r;
  186 
  187         r = hammer_rec_cmp(&cursor->key_beg, rec);
  188         if (r > 1)
  189                 return(-1);
  190         r = hammer_rec_cmp(&cursor->key_end, rec);
  191         if (r < -1)
  192                 return(1);
  193         return(0);
  194 }
  195 
  196 /*
  197  * This compare function is used when simply looking up key_beg.
  198  */
  199 static
  200 int
  201 hammer_rec_find_cmp(hammer_record_t rec, void *data)
  202 {
  203         hammer_cursor_t cursor = data;
  204         int r;
  205 
  206         r = hammer_rec_cmp(&cursor->key_beg, rec);
  207         if (r > 1)
  208                 return(-1);
  209         if (r < -1)
  210                 return(1);
  211         return(0);
  212 }
  213 
  214 /*
  215  * Locate blocks within the truncation range.  Partial blocks do not count.
  216  */
  217 static
  218 int
  219 hammer_rec_trunc_cmp(hammer_record_t rec, void *data)
  220 {
  221         struct rec_trunc_info *info = data;
  222 
  223         if (rec->leaf.base.rec_type < info->rec_type)
  224                 return(-1);
  225         if (rec->leaf.base.rec_type > info->rec_type)
  226                 return(1);
  227 
  228         switch(rec->leaf.base.rec_type) {
  229         case HAMMER_RECTYPE_DB:
  230                 /*
  231                  * DB record key is not beyond the truncation point, retain.
  232                  */
  233                 if (rec->leaf.base.key < info->trunc_off)
  234                         return(-1);
  235                 break;
  236         case HAMMER_RECTYPE_DATA:
  237                 /*
  238                  * DATA record offset start is not beyond the truncation point,
  239                  * retain.
  240                  */
  241                 if (rec->leaf.base.key - rec->leaf.data_len < info->trunc_off)
  242                         return(-1);
  243                 break;
  244         default:
  245                 panic("hammer_rec_trunc_cmp: unexpected record type");
  246         }
  247 
  248         /*
  249          * The record start is >= the truncation point, return match,
  250          * the record should be destroyed.
  251          */
  252         return(0);
  253 }
  254 
  255 RB_GENERATE(hammer_rec_rb_tree, hammer_record, rb_node, hammer_rec_rb_compare);
  256 
  257 /*
  258  * Allocate a record for the caller to finish filling in.  The record is
  259  * returned referenced.
  260  */
  261 hammer_record_t
  262 hammer_alloc_mem_record(hammer_inode_t ip, int data_len)
  263 {
  264         hammer_record_t record;
  265         hammer_mount_t hmp;
  266 
  267         hmp = ip->hmp;
  268         ++hammer_count_records;
  269         record = kmalloc(sizeof(*record), hmp->m_misc,
  270                          M_WAITOK | M_ZERO | M_USE_RESERVE);
  271         record->flush_state = HAMMER_FST_IDLE;
  272         record->ip = ip;
  273         record->leaf.base.btype = HAMMER_BTREE_TYPE_RECORD;
  274         record->leaf.data_len = data_len;
  275         hammer_ref(&record->lock);
  276 
  277         if (data_len) {
  278                 record->data = kmalloc(data_len, hmp->m_misc, M_WAITOK | M_ZERO);
  279                 record->flags |= HAMMER_RECF_ALLOCDATA;
  280                 ++hammer_count_record_datas;
  281         }
  282 
  283         return (record);
  284 }
  285 
  286 void
  287 hammer_wait_mem_record_ident(hammer_record_t record, const char *ident)
  288 {
  289         while (record->flush_state == HAMMER_FST_FLUSH) {
  290                 record->flags |= HAMMER_RECF_WANTED;
  291                 tsleep(record, 0, ident, 0);
  292         }
  293 }
  294 
  295 /*
  296  * Called from the backend, hammer_inode.c, after a record has been
  297  * flushed to disk.  The record has been exclusively locked by the
  298  * caller and interlocked with BE.
  299  *
  300  * We clean up the state, unlock, and release the record (the record
  301  * was referenced by the fact that it was in the HAMMER_FST_FLUSH state).
  302  */
  303 void
  304 hammer_flush_record_done(hammer_record_t record, int error)
  305 {
  306         hammer_inode_t target_ip;
  307 
  308         KKASSERT(record->flush_state == HAMMER_FST_FLUSH);
  309         KKASSERT(record->flags & HAMMER_RECF_INTERLOCK_BE);
  310 
  311         /*
  312          * If an error occured, the backend was unable to sync the
  313          * record to its media.  Leave the record intact.
  314          */
  315         if (error) {
  316                 hammer_critical_error(record->ip->hmp, record->ip, error,
  317                                       "while flushing record");
  318         }
  319 
  320         --record->flush_group->refs;
  321         record->flush_group = NULL;
  322 
  323         /*
  324          * Adjust the flush state and dependancy based on success or
  325          * failure.
  326          */
  327         if (record->flags & (HAMMER_RECF_DELETED_BE | HAMMER_RECF_COMMITTED)) {
  328                 if ((target_ip = record->target_ip) != NULL) {
  329                         TAILQ_REMOVE(&target_ip->target_list, record,
  330                                      target_entry);
  331                         record->target_ip = NULL;
  332                         hammer_test_inode(target_ip);
  333                 }
  334                 record->flush_state = HAMMER_FST_IDLE;
  335         } else {
  336                 if (record->target_ip) {
  337                         record->flush_state = HAMMER_FST_SETUP;
  338                         hammer_test_inode(record->ip);
  339                         hammer_test_inode(record->target_ip);
  340                 } else {
  341                         record->flush_state = HAMMER_FST_IDLE;
  342                 }
  343         }
  344         record->flags &= ~HAMMER_RECF_INTERLOCK_BE;
  345 
  346         /*
  347          * Cleanup
  348          */
  349         if (record->flags & HAMMER_RECF_WANTED) {
  350                 record->flags &= ~HAMMER_RECF_WANTED;
  351                 wakeup(record);
  352         }
  353         hammer_rel_mem_record(record);
  354 }
  355 
  356 /*
  357  * Release a memory record.  Records marked for deletion are immediately
  358  * removed from the RB-Tree but otherwise left intact until the last ref
  359  * goes away.
  360  */
  361 void
  362 hammer_rel_mem_record(struct hammer_record *record)
  363 {
  364         hammer_mount_t hmp;
  365         hammer_reserve_t resv;
  366         hammer_inode_t ip;
  367         hammer_inode_t target_ip;
  368         int diddrop;
  369 
  370         hammer_rel(&record->lock);
  371 
  372         if (hammer_norefs(&record->lock)) {
  373                 /*
  374                  * Upon release of the last reference wakeup any waiters.
  375                  * The record structure may get destroyed so callers will
  376                  * loop up and do a relookup.
  377                  *
  378                  * WARNING!  Record must be removed from RB-TREE before we
  379                  * might possibly block.  hammer_test_inode() can block!
  380                  */
  381                 ip = record->ip;
  382                 hmp = ip->hmp;
  383 
  384                 /*
  385                  * Upon release of the last reference a record marked deleted
  386                  * by the front or backend, or committed by the backend,
  387                  * is destroyed.
  388                  */
  389                 if (record->flags & (HAMMER_RECF_DELETED_FE |
  390                                      HAMMER_RECF_DELETED_BE |
  391                                      HAMMER_RECF_COMMITTED)) {
  392                         KKASSERT(hammer_isactive(&ip->lock) > 0);
  393                         KKASSERT(record->flush_state != HAMMER_FST_FLUSH);
  394 
  395                         /*
  396                          * target_ip may have zero refs, we have to ref it
  397                          * to prevent it from being ripped out from under
  398                          * us.
  399                          */
  400                         if ((target_ip = record->target_ip) != NULL) {
  401                                 TAILQ_REMOVE(&target_ip->target_list,
  402                                              record, target_entry);
  403                                 record->target_ip = NULL;
  404                                 hammer_ref(&target_ip->lock);
  405                         }
  406 
  407                         /*
  408                          * Remove the record from the B-Tree
  409                          */
  410                         if (record->flags & HAMMER_RECF_ONRBTREE) {
  411                                 RB_REMOVE(hammer_rec_rb_tree,
  412                                           &record->ip->rec_tree,
  413                                           record);
  414                                 record->flags &= ~HAMMER_RECF_ONRBTREE;
  415                                 KKASSERT(ip->rsv_recs > 0);
  416                                 if (RB_EMPTY(&record->ip->rec_tree)) {
  417                                         record->ip->flags &=
  418                                                         ~HAMMER_INODE_XDIRTY;
  419                                         record->ip->sync_flags &=
  420                                                         ~HAMMER_INODE_XDIRTY;
  421                                 }
  422                                 diddrop = 1;
  423                         } else {
  424                                 diddrop = 0;
  425                         }
  426 
  427                         /*
  428                          * We must wait for any direct-IO to complete before
  429                          * we can destroy the record because the bio may
  430                          * have a reference to it.
  431                          */
  432                         if (record->gflags &
  433                            (HAMMER_RECG_DIRECT_IO | HAMMER_RECG_DIRECT_INVAL)) {
  434                                 hammer_io_direct_wait(record);
  435                         }
  436 
  437                         /*
  438                          * Account for the completion after the direct IO
  439                          * has completed.
  440                          */
  441                         if (diddrop) {
  442                                 --hmp->rsv_recs;
  443                                 --ip->rsv_recs;
  444                                 hmp->rsv_databytes -= record->leaf.data_len;
  445 
  446                                 if (RB_EMPTY(&record->ip->rec_tree))
  447                                         hammer_test_inode(record->ip);
  448                                 if ((ip->flags & HAMMER_INODE_RECSW) &&
  449                                     ip->rsv_recs <= hammer_limit_inode_recs/2) {
  450                                         ip->flags &= ~HAMMER_INODE_RECSW;
  451                                         wakeup(&ip->rsv_recs);
  452                                 }
  453                         }
  454 
  455                         /*
  456                          * Do this test after removing record from the B-Tree.
  457                          */
  458                         if (target_ip) {
  459                                 hammer_test_inode(target_ip);
  460                                 hammer_rel_inode(target_ip, 0);
  461                         }
  462 
  463                         if (record->flags & HAMMER_RECF_ALLOCDATA) {
  464                                 --hammer_count_record_datas;
  465                                 kfree(record->data, hmp->m_misc);
  466                                 record->flags &= ~HAMMER_RECF_ALLOCDATA;
  467                         }
  468 
  469                         /*
  470                          * Release the reservation.
  471                          *
  472                          * If the record was not committed we can theoretically
  473                          * undo the reservation.  However, doing so might
  474                          * create weird edge cases with the ordering of
  475                          * direct writes because the related buffer cache
  476                          * elements are per-vnode.  So we don't try.
  477                          */
  478                         if ((resv = record->resv) != NULL) {
  479                                 /* XXX undo leaf.data_offset,leaf.data_len */
  480                                 hammer_blockmap_reserve_complete(hmp, resv);
  481                                 record->resv = NULL;
  482                         }
  483                         record->data = NULL;
  484                         --hammer_count_records;
  485                         kfree(record, hmp->m_misc);
  486                 }
  487         }
  488 }
  489 
  490 /*
  491  * Record visibility depends on whether the record is being accessed by
  492  * the backend or the frontend.  Backend tests ignore the frontend delete
  493  * flag.  Frontend tests do NOT ignore the backend delete/commit flags and
  494  * must also check for commit races.
  495  *
  496  * Return non-zero if the record is visible, zero if it isn't or if it is
  497  * deleted.  Returns 0 if the record has been comitted (unless the special
  498  * delete-visibility flag is set).  A committed record must be located
  499  * via the media B-Tree.  Returns non-zero if the record is good.
  500  *
  501  * If HAMMER_CURSOR_DELETE_VISIBILITY is set we allow deleted memory
  502  * records to be returned.  This is so pending deletions are detected
  503  * when using an iterator to locate an unused hash key, or when we need
  504  * to locate historical records on-disk to destroy.
  505  */
  506 static __inline
  507 int
  508 hammer_ip_iterate_mem_good(hammer_cursor_t cursor, hammer_record_t record)
  509 {
  510         if (cursor->flags & HAMMER_CURSOR_DELETE_VISIBILITY)
  511                 return(1);
  512         if (cursor->flags & HAMMER_CURSOR_BACKEND) {
  513                 if (record->flags & (HAMMER_RECF_DELETED_BE |
  514                                      HAMMER_RECF_COMMITTED)) {
  515                         return(0);
  516                 }
  517         } else {
  518                 if (record->flags & (HAMMER_RECF_DELETED_FE |
  519                                      HAMMER_RECF_DELETED_BE |
  520                                      HAMMER_RECF_COMMITTED)) {
  521                         return(0);
  522                 }
  523         }
  524         return(1);
  525 }
  526 
  527 /*
  528  * This callback is used as part of the RB_SCAN function for in-memory
  529  * records.  We terminate it (return -1) as soon as we get a match.
  530  *
  531  * This routine is used by frontend code.
  532  *
  533  * The primary compare code does not account for ASOF lookups.  This
  534  * code handles that case as well as a few others.
  535  */
  536 static
  537 int
  538 hammer_rec_scan_callback(hammer_record_t rec, void *data)
  539 {
  540         hammer_cursor_t cursor = data;
  541 
  542         /*
  543          * We terminate on success, so this should be NULL on entry.
  544          */
  545         KKASSERT(cursor->iprec == NULL);
  546 
  547         /*
  548          * Skip if the record was marked deleted or committed.
  549          */
  550         if (hammer_ip_iterate_mem_good(cursor, rec) == 0)
  551                 return(0);
  552 
  553         /*
  554          * Skip if not visible due to our as-of TID
  555          */
  556         if (cursor->flags & HAMMER_CURSOR_ASOF) {
  557                 if (cursor->asof < rec->leaf.base.create_tid)
  558                         return(0);
  559                 if (rec->leaf.base.delete_tid &&
  560                     cursor->asof >= rec->leaf.base.delete_tid) {
  561                         return(0);
  562                 }
  563         }
  564 
  565         /*
  566          * ref the record.  The record is protected from backend B-Tree
  567          * interactions by virtue of the cursor's IP lock.
  568          */
  569         hammer_ref(&rec->lock);
  570 
  571         /*
  572          * The record may have been deleted or committed while we
  573          * were blocked.  XXX remove?
  574          */
  575         if (hammer_ip_iterate_mem_good(cursor, rec) == 0) {
  576                 hammer_rel_mem_record(rec);
  577                 return(0);
  578         }
  579 
  580         /*
  581          * Set the matching record and stop the scan.
  582          */
  583         cursor->iprec = rec;
  584         return(-1);
  585 }
  586 
  587 
  588 /*
  589  * Lookup an in-memory record given the key specified in the cursor.  Works
  590  * just like hammer_btree_lookup() but operates on an inode's in-memory
  591  * record list.
  592  *
  593  * The lookup must fail if the record is marked for deferred deletion.
  594  *
  595  * The API for mem/btree_lookup() does not mess with the ATE/EOF bits.
  596  */
  597 static
  598 int
  599 hammer_mem_lookup(hammer_cursor_t cursor)
  600 {
  601         KKASSERT(cursor->ip);
  602         if (cursor->iprec) {
  603                 hammer_rel_mem_record(cursor->iprec);
  604                 cursor->iprec = NULL;
  605         }
  606         hammer_rec_rb_tree_RB_SCAN(&cursor->ip->rec_tree, hammer_rec_find_cmp,
  607                                    hammer_rec_scan_callback, cursor);
  608 
  609         return (cursor->iprec ? 0 : ENOENT);
  610 }
  611 
  612 /*
  613  * hammer_mem_first() - locate the first in-memory record matching the
  614  * cursor within the bounds of the key range.
  615  *
  616  * WARNING!  API is slightly different from btree_first().  hammer_mem_first()
  617  * will set ATEMEM the same as MEMEOF, and does not return any error.
  618  */
  619 static
  620 void
  621 hammer_mem_first(hammer_cursor_t cursor)
  622 {
  623         hammer_inode_t ip;
  624 
  625         ip = cursor->ip;
  626         KKASSERT(ip != NULL);
  627 
  628         if (cursor->iprec) {
  629                 hammer_rel_mem_record(cursor->iprec);
  630                 cursor->iprec = NULL;
  631         }
  632         hammer_rec_rb_tree_RB_SCAN(&ip->rec_tree, hammer_rec_scan_cmp,
  633                                    hammer_rec_scan_callback, cursor);
  634 
  635         if (cursor->iprec)
  636                 cursor->flags &= ~(HAMMER_CURSOR_MEMEOF | HAMMER_CURSOR_ATEMEM);
  637         else
  638                 cursor->flags |= HAMMER_CURSOR_MEMEOF | HAMMER_CURSOR_ATEMEM;
  639 }
  640 
  641 /************************************************************************
  642  *                   HAMMER IN-MEMORY RECORD FUNCTIONS                  *
  643  ************************************************************************
  644  *
  645  * These functions manipulate in-memory records.  Such records typically
  646  * exist prior to being committed to disk or indexed via the on-disk B-Tree.
  647  */
  648 
  649 /*
  650  * Add a directory entry (dip,ncp) which references inode (ip).
  651  *
  652  * Note that the low 32 bits of the namekey are set temporarily to create
  653  * a unique in-memory record, and may be modified a second time when the
  654  * record is synchronized to disk.  In particular, the low 32 bits cannot be
  655  * all 0's when synching to disk, which is not handled here.
  656  *
  657  * NOTE: bytes does not include any terminating \0 on name, and name might
  658  * not be terminated.
  659  */
  660 int
  661 hammer_ip_add_directory(struct hammer_transaction *trans,
  662                      struct hammer_inode *dip, const char *name, int bytes,
  663                      struct hammer_inode *ip)
  664 {
  665         struct hammer_cursor cursor;
  666         hammer_record_t record;
  667         int error;
  668         u_int32_t max_iterations;
  669 
  670         KKASSERT(dip->ino_data.obj_type == HAMMER_OBJTYPE_DIRECTORY);
  671 
  672         record = hammer_alloc_mem_record(dip, HAMMER_ENTRY_SIZE(bytes));
  673 
  674         record->type = HAMMER_MEM_RECORD_ADD;
  675         record->leaf.base.localization = dip->obj_localization +
  676                                          hammer_dir_localization(dip);
  677         record->leaf.base.obj_id = dip->obj_id;
  678         record->leaf.base.key = hammer_directory_namekey(dip, name, bytes,
  679                                                          &max_iterations);
  680         record->leaf.base.rec_type = HAMMER_RECTYPE_DIRENTRY;
  681         record->leaf.base.obj_type = ip->ino_leaf.base.obj_type;
  682         record->data->entry.obj_id = ip->obj_id;
  683         record->data->entry.localization = ip->obj_localization;
  684         bcopy(name, record->data->entry.name, bytes);
  685 
  686         ++ip->ino_data.nlinks;
  687         ip->ino_data.ctime = trans->time;
  688         hammer_modify_inode(trans, ip, HAMMER_INODE_DDIRTY);
  689 
  690         /*
  691          * Find an unused namekey.  Both the in-memory record tree and
  692          * the B-Tree are checked.  We do not want historically deleted
  693          * names to create a collision as our iteration space may be limited,
  694          * and since create_tid wouldn't match anyway an ASOF search
  695          * must be used to locate collisions.
  696          *
  697          * delete-visibility is set so pending deletions do not give us
  698          * a false-negative on our ability to use an iterator.
  699          *
  700          * The iterator must not rollover the key.  Directory keys only
  701          * use the positive key space.
  702          */
  703         hammer_init_cursor(trans, &cursor, &dip->cache[1], dip);
  704         cursor.key_beg = record->leaf.base;
  705         cursor.flags |= HAMMER_CURSOR_ASOF;
  706         cursor.flags |= HAMMER_CURSOR_DELETE_VISIBILITY;
  707         cursor.asof = ip->obj_asof;
  708 
  709         while (hammer_ip_lookup(&cursor) == 0) {
  710                 ++record->leaf.base.key;
  711                 KKASSERT(record->leaf.base.key > 0);
  712                 cursor.key_beg.key = record->leaf.base.key;
  713                 if (--max_iterations == 0) {
  714                         hammer_rel_mem_record(record);
  715                         error = ENOSPC;
  716                         goto failed;
  717                 }
  718         }
  719 
  720         /*
  721          * The target inode and the directory entry are bound together.
  722          */
  723         record->target_ip = ip;
  724         record->flush_state = HAMMER_FST_SETUP;
  725         TAILQ_INSERT_TAIL(&ip->target_list, record, target_entry);
  726 
  727         /*
  728          * The inode now has a dependancy and must be taken out of the idle
  729          * state.  An inode not in an idle state is given an extra reference.
  730          *
  731          * When transitioning to a SETUP state flag for an automatic reflush
  732          * when the dependancies are disposed of if someone is waiting on
  733          * the inode.
  734          */
  735         if (ip->flush_state == HAMMER_FST_IDLE) {
  736                 hammer_ref(&ip->lock);
  737                 ip->flush_state = HAMMER_FST_SETUP;
  738                 if (ip->flags & HAMMER_INODE_FLUSHW)
  739                         ip->flags |= HAMMER_INODE_REFLUSH;
  740         }
  741         error = hammer_mem_add(record);
  742         if (error == 0) {
  743                 dip->ino_data.mtime = trans->time;
  744                 hammer_modify_inode(trans, dip, HAMMER_INODE_MTIME);
  745         }
  746 failed:
  747         hammer_done_cursor(&cursor);
  748         return(error);
  749 }
  750 
  751 /*
  752  * Delete the directory entry and update the inode link count.  The
  753  * cursor must be seeked to the directory entry record being deleted.
  754  *
  755  * The related inode should be share-locked by the caller.  The caller is
  756  * on the frontend.  It could also be NULL indicating that the directory
  757  * entry being removed has no related inode.
  758  *
  759  * This function can return EDEADLK requiring the caller to terminate
  760  * the cursor, any locks, wait on the returned record, and retry.
  761  */
  762 int
  763 hammer_ip_del_directory(struct hammer_transaction *trans,
  764                      hammer_cursor_t cursor, struct hammer_inode *dip,
  765                      struct hammer_inode *ip)
  766 {
  767         hammer_record_t record;
  768         int error;
  769 
  770         if (hammer_cursor_inmem(cursor)) {
  771                 /*
  772                  * In-memory (unsynchronized) records can simply be freed.
  773                  *
  774                  * Even though the HAMMER_RECF_DELETED_FE flag is ignored
  775                  * by the backend, we must still avoid races against the
  776                  * backend potentially syncing the record to the media.
  777                  *
  778                  * We cannot call hammer_ip_delete_record(), that routine may
  779                  * only be called from the backend.
  780                  */
  781                 record = cursor->iprec;
  782                 if (record->flags & (HAMMER_RECF_INTERLOCK_BE |
  783                                      HAMMER_RECF_DELETED_BE |
  784                                      HAMMER_RECF_COMMITTED)) {
  785                         KKASSERT(cursor->deadlk_rec == NULL);
  786                         hammer_ref(&record->lock);
  787                         cursor->deadlk_rec = record;
  788                         error = EDEADLK;
  789                 } else {
  790                         KKASSERT(record->type == HAMMER_MEM_RECORD_ADD);
  791                         record->flags |= HAMMER_RECF_DELETED_FE;
  792                         error = 0;
  793                 }
  794         } else {
  795                 /*
  796                  * If the record is on-disk we have to queue the deletion by
  797                  * the record's key.  This also causes lookups to skip the
  798                  * record (lookups for the purposes of finding an unused
  799                  * directory key do not skip the record).
  800                  */
  801                 KKASSERT(dip->flags &
  802                          (HAMMER_INODE_ONDISK | HAMMER_INODE_DONDISK));
  803                 record = hammer_alloc_mem_record(dip, 0);
  804                 record->type = HAMMER_MEM_RECORD_DEL;
  805                 record->leaf.base = cursor->leaf->base;
  806                 KKASSERT(dip->obj_id == record->leaf.base.obj_id);
  807 
  808                 /*
  809                  * ip may be NULL, indicating the deletion of a directory
  810                  * entry which has no related inode.
  811                  */
  812                 record->target_ip = ip;
  813                 if (ip) {
  814                         record->flush_state = HAMMER_FST_SETUP;
  815                         TAILQ_INSERT_TAIL(&ip->target_list, record,
  816                                           target_entry);
  817                 } else {
  818                         record->flush_state = HAMMER_FST_IDLE;
  819                 }
  820 
  821                 /*
  822                  * The inode now has a dependancy and must be taken out of
  823                  * the idle state.  An inode not in an idle state is given
  824                  * an extra reference.
  825                  *
  826                  * When transitioning to a SETUP state flag for an automatic
  827                  * reflush when the dependancies are disposed of if someone
  828                  * is waiting on the inode.
  829                  */
  830                 if (ip && ip->flush_state == HAMMER_FST_IDLE) {
  831                         hammer_ref(&ip->lock);
  832                         ip->flush_state = HAMMER_FST_SETUP;
  833                         if (ip->flags & HAMMER_INODE_FLUSHW)
  834                                 ip->flags |= HAMMER_INODE_REFLUSH;
  835                 }
  836 
  837                 error = hammer_mem_add(record);
  838         }
  839 
  840         /*
  841          * One less link.  The file may still be open in the OS even after
  842          * all links have gone away.
  843          *
  844          * We have to terminate the cursor before syncing the inode to
  845          * avoid deadlocking against ourselves.  XXX this may no longer
  846          * be true.
  847          *
  848          * If nlinks drops to zero and the vnode is inactive (or there is
  849          * no vnode), call hammer_inode_unloadable_check() to zonk the
  850          * inode.  If we don't do this here the inode will not be destroyed
  851          * on-media until we unmount.
  852          */
  853         if (error == 0) {
  854                 if (ip) {
  855                         --ip->ino_data.nlinks;  /* do before we might block */
  856                         ip->ino_data.ctime = trans->time;
  857                 }
  858                 dip->ino_data.mtime = trans->time;
  859                 hammer_modify_inode(trans, dip, HAMMER_INODE_MTIME);
  860                 if (ip) {
  861                         hammer_modify_inode(trans, ip, HAMMER_INODE_DDIRTY);
  862                         if (ip->ino_data.nlinks == 0 &&
  863                             (ip->vp == NULL || (ip->vp->v_flag & VINACTIVE))) {
  864                                 hammer_done_cursor(cursor);
  865                                 hammer_inode_unloadable_check(ip, 1);
  866                                 hammer_flush_inode(ip, 0);
  867                         }
  868                 }
  869 
  870         }
  871         return(error);
  872 }
  873 
  874 /*
  875  * Add a record to an inode.
  876  *
  877  * The caller must allocate the record with hammer_alloc_mem_record(ip) and
  878  * initialize the following additional fields:
  879  *
  880  * The related inode should be share-locked by the caller.  The caller is
  881  * on the frontend.
  882  *
  883  * record->rec.entry.base.base.key
  884  * record->rec.entry.base.base.rec_type
  885  * record->rec.entry.base.base.data_len
  886  * record->data         (a copy will be kmalloc'd if it cannot be embedded)
  887  */
  888 int
  889 hammer_ip_add_record(struct hammer_transaction *trans, hammer_record_t record)
  890 {
  891         hammer_inode_t ip = record->ip;
  892         int error;
  893 
  894         KKASSERT(record->leaf.base.localization != 0);
  895         record->leaf.base.obj_id = ip->obj_id;
  896         record->leaf.base.obj_type = ip->ino_leaf.base.obj_type;
  897         error = hammer_mem_add(record);
  898         return(error);
  899 }
  900 
  901 /*
  902  * Locate a pre-existing bulk record in memory.  The caller wishes to
  903  * replace the record with a new one.  The existing record may have a
  904  * different length (and thus a different key) so we have to use an
  905  * overlap check function.
  906  */
  907 static hammer_record_t
  908 hammer_ip_get_bulk(hammer_record_t record)
  909 {
  910         struct hammer_bulk_info info;
  911         hammer_inode_t ip = record->ip;
  912 
  913         info.record = record;
  914         info.conflict = NULL;
  915         hammer_rec_rb_tree_RB_SCAN(&ip->rec_tree, hammer_rec_overlap_cmp,
  916                                    hammer_bulk_scan_callback, &info);
  917 
  918         return(info.conflict);  /* may be NULL */
  919 }
  920 
  921 /*
  922  * Take records vetted by overlap_cmp.  The first non-deleted record
  923  * (if any) stops the scan.
  924  */
  925 static int
  926 hammer_bulk_scan_callback(hammer_record_t record, void *data)
  927 {
  928         struct hammer_bulk_info *info = data;
  929 
  930         if (record->flags & (HAMMER_RECF_DELETED_FE | HAMMER_RECF_DELETED_BE |
  931                              HAMMER_RECF_COMMITTED)) {
  932                 return(0);
  933         }
  934         hammer_ref(&record->lock);
  935         info->conflict = record;
  936         return(-1);                     /* stop scan */
  937 }
  938 
  939 /*
  940  * Reserve blockmap space placemarked with an in-memory record.  
  941  *
  942  * This routine is called by the frontend in order to be able to directly
  943  * flush a buffer cache buffer.  The frontend has locked the related buffer
  944  * cache buffers and we should be able to manipulate any overlapping
  945  * in-memory records.
  946  *
  947  * The caller is responsible for adding the returned record and deleting
  948  * the returned conflicting record (if any), typically by calling
  949  * hammer_ip_replace_bulk() (via hammer_io_direct_write()).
  950  */
  951 hammer_record_t
  952 hammer_ip_add_bulk(hammer_inode_t ip, off_t file_offset, void *data, int bytes,
  953                    int *errorp)
  954 {
  955         hammer_record_t record;
  956         hammer_dedup_cache_t dcp;
  957         hammer_crc_t crc;
  958         int zone;
  959 
  960         /*
  961          * Create a record to cover the direct write.  The record cannot
  962          * be added to the in-memory RB tree here as it might conflict
  963          * with an existing memory record.  See hammer_io_direct_write().
  964          *
  965          * The backend is responsible for finalizing the space reserved in
  966          * this record.
  967          *
  968          * XXX bytes not aligned, depend on the reservation code to
  969          * align the reservation.
  970          */
  971         record = hammer_alloc_mem_record(ip, 0);
  972         zone = (bytes >= HAMMER_BUFSIZE) ? HAMMER_ZONE_LARGE_DATA_INDEX :
  973                                            HAMMER_ZONE_SMALL_DATA_INDEX;
  974         if (bytes == 0)
  975                 crc = 0;
  976         else
  977                 crc = crc32(data, bytes);
  978 
  979         if (hammer_live_dedup == 0)
  980                 goto nodedup;
  981         if ((dcp = hammer_dedup_cache_lookup(ip->hmp, crc)) != NULL) {
  982                 struct hammer_dedup_cache tmp = *dcp;
  983 
  984                 record->resv = hammer_blockmap_reserve_dedup(ip->hmp, zone,
  985                         bytes, tmp.data_offset, errorp);
  986                 if (record->resv == NULL)
  987                         goto nodedup;
  988 
  989                 if (!hammer_dedup_validate(&tmp, zone, bytes, data)) {
  990                         hammer_blockmap_reserve_complete(ip->hmp, record->resv);
  991                         goto nodedup;
  992                 }
  993 
  994                 record->leaf.data_offset = tmp.data_offset;
  995                 record->flags |= HAMMER_RECF_DEDUPED;
  996         } else {
  997 nodedup:
  998                 record->resv = hammer_blockmap_reserve(ip->hmp, zone, bytes,
  999                        &record->leaf.data_offset, errorp);
 1000                 if (record->resv == NULL) {
 1001                         kprintf("hammer_ip_add_bulk: reservation failed\n");
 1002                         hammer_rel_mem_record(record);
 1003                         return(NULL);
 1004                 }
 1005         }
 1006 
 1007         record->type = HAMMER_MEM_RECORD_DATA;
 1008         record->leaf.base.rec_type = HAMMER_RECTYPE_DATA;
 1009         record->leaf.base.obj_type = ip->ino_leaf.base.obj_type;
 1010         record->leaf.base.obj_id = ip->obj_id;
 1011         record->leaf.base.key = file_offset + bytes;
 1012         record->leaf.base.localization = ip->obj_localization +
 1013                                          HAMMER_LOCALIZE_MISC;
 1014         record->leaf.data_len = bytes;
 1015         record->leaf.data_crc = crc;
 1016         KKASSERT(*errorp == 0);
 1017 
 1018         return(record);
 1019 }
 1020 
 1021 /*
 1022  * Called by hammer_io_direct_write() prior to any possible completion
 1023  * of the BIO to emplace the memory record associated with the I/O and
 1024  * to replace any prior memory record which might still be active.
 1025  *
 1026  * Setting the FE deleted flag on the old record (if any) avoids any RB
 1027  * tree insertion conflict, amoung other things.
 1028  *
 1029  * This has to be done prior to the caller completing any related buffer
 1030  * cache I/O or a reinstantiation of the buffer may load data from the
 1031  * old media location instead of the new media location.  The holding
 1032  * of the locked buffer cache buffer serves to interlock the record
 1033  * replacement operation.
 1034  */
 1035 void
 1036 hammer_ip_replace_bulk(hammer_mount_t hmp, hammer_record_t record)
 1037 {
 1038         hammer_record_t conflict;
 1039         int error __debugvar;
 1040 
 1041         while ((conflict = hammer_ip_get_bulk(record)) != NULL) {
 1042                 if ((conflict->flags & HAMMER_RECF_INTERLOCK_BE) == 0) {
 1043                         conflict->flags |= HAMMER_RECF_DELETED_FE;
 1044                         break;
 1045                 }
 1046                 conflict->flags |= HAMMER_RECF_WANTED;
 1047                 tsleep(conflict, 0, "hmrrc3", 0);
 1048                 hammer_rel_mem_record(conflict);
 1049         }
 1050         error = hammer_mem_add(record);
 1051         if (conflict)
 1052                 hammer_rel_mem_record(conflict);
 1053         KKASSERT(error == 0);
 1054 }
 1055 
 1056 /*
 1057  * Frontend truncation code.  Scan in-memory records only.  On-disk records
 1058  * and records in a flushing state are handled by the backend.  The vnops
 1059  * setattr code will handle the block containing the truncation point.
 1060  *
 1061  * Partial blocks are not deleted.
 1062  *
 1063  * This code is only called on regular files.
 1064  */
 1065 int
 1066 hammer_ip_frontend_trunc(struct hammer_inode *ip, off_t file_size)
 1067 {
 1068         struct rec_trunc_info info;
 1069 
 1070         switch(ip->ino_data.obj_type) {
 1071         case HAMMER_OBJTYPE_REGFILE:
 1072                 info.rec_type = HAMMER_RECTYPE_DATA;
 1073                 break;
 1074         case HAMMER_OBJTYPE_DBFILE:
 1075                 info.rec_type = HAMMER_RECTYPE_DB;
 1076                 break;
 1077         default:
 1078                 return(EINVAL);
 1079         }
 1080         info.trunc_off = file_size;
 1081         hammer_rec_rb_tree_RB_SCAN(&ip->rec_tree, hammer_rec_trunc_cmp,
 1082                                    hammer_frontend_trunc_callback, &info);
 1083         return(0);
 1084 }
 1085 
 1086 /*
 1087  * Scan callback for frontend records to destroy during a truncation.
 1088  * We must ensure that DELETED_FE is set on the record or the frontend
 1089  * will get confused in future read() calls.
 1090  *
 1091  * NOTE: DELETED_FE cannot be set while the record interlock (BE) is held.
 1092  *       In this rare case we must wait for the interlock to be cleared.
 1093  *
 1094  * NOTE: This function is only called on regular files.  There are further
 1095  *       restrictions to the setting of DELETED_FE on directory records
 1096  *       undergoing a flush due to sensitive inode link count calculations.
 1097  */
 1098 static int
 1099 hammer_frontend_trunc_callback(hammer_record_t record, void *data __unused)
 1100 {
 1101         if (record->flags & HAMMER_RECF_DELETED_FE)
 1102                 return(0);
 1103 #if 0
 1104         if (record->flush_state == HAMMER_FST_FLUSH)
 1105                 return(0);
 1106 #endif
 1107         hammer_ref(&record->lock);
 1108         while (record->flags & HAMMER_RECF_INTERLOCK_BE)
 1109                 hammer_wait_mem_record_ident(record, "hmmtrr");
 1110         record->flags |= HAMMER_RECF_DELETED_FE;
 1111         hammer_rel_mem_record(record);
 1112         return(0);
 1113 }
 1114 
 1115 /*
 1116  * Return 1 if the caller must check for and delete existing records
 1117  * before writing out a new data record.
 1118  *
 1119  * Return 0 if the caller can just insert the record into the B-Tree without
 1120  * checking.
 1121  */
 1122 static int
 1123 hammer_record_needs_overwrite_delete(hammer_record_t record)
 1124 {
 1125         hammer_inode_t ip = record->ip;
 1126         int64_t file_offset;
 1127         int r;
 1128 
 1129         if (ip->ino_data.obj_type == HAMMER_OBJTYPE_DBFILE)
 1130                 file_offset = record->leaf.base.key;
 1131         else
 1132                 file_offset = record->leaf.base.key - record->leaf.data_len;
 1133         r = (file_offset < ip->save_trunc_off);
 1134         if (ip->ino_data.obj_type == HAMMER_OBJTYPE_DBFILE) {
 1135                 if (ip->save_trunc_off <= record->leaf.base.key)
 1136                         ip->save_trunc_off = record->leaf.base.key + 1;
 1137         } else {
 1138                 if (ip->save_trunc_off < record->leaf.base.key)
 1139                         ip->save_trunc_off = record->leaf.base.key;
 1140         }
 1141         return(r);
 1142 }
 1143 
 1144 /*
 1145  * Backend code.  Sync a record to the media.
 1146  */
 1147 int
 1148 hammer_ip_sync_record_cursor(hammer_cursor_t cursor, hammer_record_t record)
 1149 {
 1150         hammer_transaction_t trans = cursor->trans;
 1151         int64_t file_offset;
 1152         int bytes;
 1153         void *bdata;
 1154         int error;
 1155         int doprop;
 1156 
 1157         KKASSERT(record->flush_state == HAMMER_FST_FLUSH);
 1158         KKASSERT(record->flags & HAMMER_RECF_INTERLOCK_BE);
 1159         KKASSERT(record->leaf.base.localization != 0);
 1160 
 1161         /*
 1162          * Any direct-write related to the record must complete before we
 1163          * can sync the record to the on-disk media.
 1164          */
 1165         if (record->gflags & (HAMMER_RECG_DIRECT_IO | HAMMER_RECG_DIRECT_INVAL))
 1166                 hammer_io_direct_wait(record);
 1167 
 1168         /*
 1169          * If this is a bulk-data record placemarker there may be an existing
 1170          * record on-disk, indicating a data overwrite.  If there is the
 1171          * on-disk record must be deleted before we can insert our new record.
 1172          *
 1173          * We've synthesized this record and do not know what the create_tid
 1174          * on-disk is, nor how much data it represents.
 1175          *
 1176          * Keep in mind that (key) for data records is (base_offset + len),
 1177          * not (base_offset).  Also, we only want to get rid of on-disk
 1178          * records since we are trying to sync our in-memory record, call
 1179          * hammer_ip_delete_range() with truncating set to 1 to make sure
 1180          * it skips in-memory records.
 1181          *
 1182          * It is ok for the lookup to return ENOENT.
 1183          *
 1184          * NOTE OPTIMIZATION: sync_trunc_off is used to determine if we have
 1185          * to call hammer_ip_delete_range() or not.  This also means we must
 1186          * update sync_trunc_off() as we write.
 1187          */
 1188         if (record->type == HAMMER_MEM_RECORD_DATA &&
 1189             hammer_record_needs_overwrite_delete(record)) {
 1190                 file_offset = record->leaf.base.key - record->leaf.data_len;
 1191                 bytes = (record->leaf.data_len + HAMMER_BUFMASK) & 
 1192                         ~HAMMER_BUFMASK;
 1193                 KKASSERT((file_offset & HAMMER_BUFMASK) == 0);
 1194                 error = hammer_ip_delete_range(
 1195                                 cursor, record->ip,
 1196                                 file_offset, file_offset + bytes - 1,
 1197                                 1);
 1198                 if (error && error != ENOENT)
 1199                         goto done;
 1200         }
 1201 
 1202         /*
 1203          * If this is a general record there may be an on-disk version
 1204          * that must be deleted before we can insert the new record.
 1205          */
 1206         if (record->type == HAMMER_MEM_RECORD_GENERAL) {
 1207                 error = hammer_delete_general(cursor, record->ip,
 1208                                               &record->leaf);
 1209                 if (error && error != ENOENT)
 1210                         goto done;
 1211         }
 1212 
 1213         /*
 1214          * Setup the cursor.
 1215          */
 1216         hammer_normalize_cursor(cursor);
 1217         cursor->key_beg = record->leaf.base;
 1218         cursor->flags &= ~HAMMER_CURSOR_INITMASK;
 1219         cursor->flags |= HAMMER_CURSOR_BACKEND;
 1220         cursor->flags &= ~HAMMER_CURSOR_INSERT;
 1221 
 1222         /*
 1223          * Records can wind up on-media before the inode itself is on-media.
 1224          * Flag the case.
 1225          */
 1226         record->ip->flags |= HAMMER_INODE_DONDISK;
 1227 
 1228         /*
 1229          * If we are deleting a directory entry an exact match must be
 1230          * found on-disk.
 1231          */
 1232         if (record->type == HAMMER_MEM_RECORD_DEL) {
 1233                 error = hammer_btree_lookup(cursor);
 1234                 if (error == 0) {
 1235                         KKASSERT(cursor->iprec == NULL);
 1236                         error = hammer_ip_delete_record(cursor, record->ip,
 1237                                                         trans->tid);
 1238                         if (error == 0) {
 1239                                 record->flags |= HAMMER_RECF_DELETED_BE |
 1240                                                  HAMMER_RECF_COMMITTED;
 1241                                 ++record->ip->rec_generation;
 1242                         }
 1243                 }
 1244                 goto done;
 1245         }
 1246 
 1247         /*
 1248          * We are inserting.
 1249          *
 1250          * Issue a lookup to position the cursor and locate the insertion
 1251          * point.  The target key should not exist.  If we are creating a
 1252          * directory entry we may have to iterate the low 32 bits of the
 1253          * key to find an unused key.
 1254          */
 1255         hammer_sync_lock_sh(trans);
 1256         cursor->flags |= HAMMER_CURSOR_INSERT;
 1257         error = hammer_btree_lookup(cursor);
 1258         if (hammer_debug_inode)
 1259                 kprintf("DOINSERT LOOKUP %d\n", error);
 1260         if (error == 0) {
 1261                 kprintf("hammer_ip_sync_record: duplicate rec "
 1262                         "at (%016llx)\n", (long long)record->leaf.base.key);
 1263                 if (hammer_debug_critical)
 1264                         Debugger("duplicate record1");
 1265                 error = EIO;
 1266         }
 1267 #if 0
 1268         if (record->type == HAMMER_MEM_RECORD_DATA)
 1269                 kprintf("sync_record  %016llx ---------------- %016llx %d\n",
 1270                         record->leaf.base.key - record->leaf.data_len,
 1271                         record->leaf.data_offset, error);
 1272 #endif
 1273 
 1274         if (error != ENOENT)
 1275                 goto done_unlock;
 1276 
 1277         /*
 1278          * Allocate the record and data.  The result buffers will be
 1279          * marked as being modified and further calls to
 1280          * hammer_modify_buffer() will result in unneeded UNDO records.
 1281          *
 1282          * Support zero-fill records (data == NULL and data_len != 0)
 1283          */
 1284         if (record->type == HAMMER_MEM_RECORD_DATA) {
 1285                 /*
 1286                  * The data portion of a bulk-data record has already been
 1287                  * committed to disk, we need only adjust the layer2
 1288                  * statistics in the same transaction as our B-Tree insert.
 1289                  */
 1290                 KKASSERT(record->leaf.data_offset != 0);
 1291                 error = hammer_blockmap_finalize(trans,
 1292                                                  record->resv,
 1293                                                  record->leaf.data_offset,
 1294                                                  record->leaf.data_len);
 1295 
 1296                 if (hammer_live_dedup == 2 &&
 1297                     (record->flags & HAMMER_RECF_DEDUPED) == 0) {
 1298                         hammer_dedup_cache_add(record->ip, &record->leaf);
 1299                 }
 1300         } else if (record->data && record->leaf.data_len) {
 1301                 /*
 1302                  * Wholely cached record, with data.  Allocate the data.
 1303                  */
 1304                 bdata = hammer_alloc_data(trans, record->leaf.data_len,
 1305                                           record->leaf.base.rec_type,
 1306                                           &record->leaf.data_offset,
 1307                                           &cursor->data_buffer,
 1308                                           0, &error);
 1309                 if (bdata == NULL)
 1310                         goto done_unlock;
 1311                 hammer_crc_set_leaf(record->data, &record->leaf);
 1312                 hammer_modify_buffer(trans, cursor->data_buffer, NULL, 0);
 1313                 bcopy(record->data, bdata, record->leaf.data_len);
 1314                 hammer_modify_buffer_done(cursor->data_buffer);
 1315         } else {
 1316                 /*
 1317                  * Wholely cached record, without data.
 1318                  */
 1319                 record->leaf.data_offset = 0;
 1320                 record->leaf.data_crc = 0;
 1321         }
 1322 
 1323         error = hammer_btree_insert(cursor, &record->leaf, &doprop);
 1324         if (hammer_debug_inode && error) {
 1325                 kprintf("BTREE INSERT error %d @ %016llx:%d key %016llx\n",
 1326                         error,
 1327                         (long long)cursor->node->node_offset,
 1328                         cursor->index,
 1329                         (long long)record->leaf.base.key);
 1330         }
 1331 
 1332         /*
 1333          * Our record is on-disk and we normally mark the in-memory version
 1334          * as having been committed (and not BE-deleted).
 1335          *
 1336          * If the record represented a directory deletion but we had to
 1337          * sync a valid directory entry to disk due to dependancies,
 1338          * we must convert the record to a covering delete so the
 1339          * frontend does not have visibility on the synced entry.
 1340          *
 1341          * WARNING: cursor's leaf pointer may have changed after do_propagation
 1342          *          returns!
 1343          */
 1344         if (error == 0) {
 1345                 if (doprop) {
 1346                         hammer_btree_do_propagation(cursor,
 1347                                                     record->ip->pfsm,
 1348                                                     &record->leaf);
 1349                 }
 1350                 if (record->flags & HAMMER_RECF_CONVERT_DELETE) {
 1351                         /*
 1352                          * Must convert deleted directory entry add
 1353                          * to a directory entry delete.
 1354                          */
 1355                         KKASSERT(record->type == HAMMER_MEM_RECORD_ADD);
 1356                         record->flags &= ~HAMMER_RECF_DELETED_FE;
 1357                         record->type = HAMMER_MEM_RECORD_DEL;
 1358                         KKASSERT(record->ip->obj_id == record->leaf.base.obj_id);
 1359                         KKASSERT(record->flush_state == HAMMER_FST_FLUSH);
 1360                         record->flags &= ~HAMMER_RECF_CONVERT_DELETE;
 1361                         KKASSERT((record->flags & (HAMMER_RECF_COMMITTED |
 1362                                                  HAMMER_RECF_DELETED_BE)) == 0);
 1363                         /* converted record is not yet committed */
 1364                         /* hammer_flush_record_done takes care of the rest */
 1365                 } else {
 1366                         /*
 1367                          * Everything went fine and we are now done with
 1368                          * this record.
 1369                          */
 1370                         record->flags |= HAMMER_RECF_COMMITTED;
 1371                         ++record->ip->rec_generation;
 1372                 }
 1373         } else {
 1374                 if (record->leaf.data_offset) {
 1375                         hammer_blockmap_free(trans, record->leaf.data_offset,
 1376                                              record->leaf.data_len);
 1377                 }
 1378         }
 1379 done_unlock:
 1380         hammer_sync_unlock(trans);
 1381 done:
 1382         return(error);
 1383 }
 1384 
 1385 /*
 1386  * Add the record to the inode's rec_tree.  The low 32 bits of a directory
 1387  * entry's key is used to deal with hash collisions in the upper 32 bits.
 1388  * A unique 64 bit key is generated in-memory and may be regenerated a
 1389  * second time when the directory record is flushed to the on-disk B-Tree.
 1390  *
 1391  * A referenced record is passed to this function.  This function
 1392  * eats the reference.  If an error occurs the record will be deleted.
 1393  *
 1394  * A copy of the temporary record->data pointer provided by the caller
 1395  * will be made.
 1396  */
 1397 int
 1398 hammer_mem_add(hammer_record_t record)
 1399 {
 1400         hammer_mount_t hmp = record->ip->hmp;
 1401 
 1402         /*
 1403          * Make a private copy of record->data
 1404          */
 1405         if (record->data)
 1406                 KKASSERT(record->flags & HAMMER_RECF_ALLOCDATA);
 1407 
 1408         /*
 1409          * Insert into the RB tree.  A unique key should have already
 1410          * been selected if this is a directory entry.
 1411          */
 1412         if (RB_INSERT(hammer_rec_rb_tree, &record->ip->rec_tree, record)) {
 1413                 record->flags |= HAMMER_RECF_DELETED_FE;
 1414                 hammer_rel_mem_record(record);
 1415                 return (EEXIST);
 1416         }
 1417         ++hmp->count_newrecords;
 1418         ++hmp->rsv_recs;
 1419         ++record->ip->rsv_recs;
 1420         record->ip->hmp->rsv_databytes += record->leaf.data_len;
 1421         record->flags |= HAMMER_RECF_ONRBTREE;
 1422         hammer_modify_inode(NULL, record->ip, HAMMER_INODE_XDIRTY);
 1423         hammer_rel_mem_record(record);
 1424         return(0);
 1425 }
 1426 
 1427 /************************************************************************
 1428  *                   HAMMER INODE MERGED-RECORD FUNCTIONS               *
 1429  ************************************************************************
 1430  *
 1431  * These functions augment the B-Tree scanning functions in hammer_btree.c
 1432  * by merging in-memory records with on-disk records.
 1433  */
 1434 
 1435 /*
 1436  * Locate a particular record either in-memory or on-disk.
 1437  *
 1438  * NOTE: This is basically a standalone routine, hammer_ip_next() may
 1439  * NOT be called to iterate results.
 1440  */
 1441 int
 1442 hammer_ip_lookup(hammer_cursor_t cursor)
 1443 {
 1444         int error;
 1445 
 1446         /*
 1447          * If the element is in-memory return it without searching the
 1448          * on-disk B-Tree
 1449          */
 1450         KKASSERT(cursor->ip);
 1451         error = hammer_mem_lookup(cursor);
 1452         if (error == 0) {
 1453                 cursor->leaf = &cursor->iprec->leaf;
 1454                 return(error);
 1455         }
 1456         if (error != ENOENT)
 1457                 return(error);
 1458 
 1459         /*
 1460          * If the inode has on-disk components search the on-disk B-Tree.
 1461          */
 1462         if ((cursor->ip->flags & (HAMMER_INODE_ONDISK|HAMMER_INODE_DONDISK)) == 0)
 1463                 return(error);
 1464         error = hammer_btree_lookup(cursor);
 1465         if (error == 0)
 1466                 error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_LEAF);
 1467         return(error);
 1468 }
 1469 
 1470 /*
 1471  * Helper for hammer_ip_first()/hammer_ip_next()
 1472  *
 1473  * NOTE: Both ATEDISK and DISKEOF will be set the same.  This sets up
 1474  * hammer_ip_first() for calling hammer_ip_next(), and sets up the re-seek
 1475  * state if hammer_ip_next() needs to re-seek.
 1476  */
 1477 static __inline
 1478 int
 1479 _hammer_ip_seek_btree(hammer_cursor_t cursor)
 1480 {
 1481         hammer_inode_t ip = cursor->ip;
 1482         int error;
 1483 
 1484         if (ip->flags & (HAMMER_INODE_ONDISK|HAMMER_INODE_DONDISK)) {
 1485                 error = hammer_btree_lookup(cursor);
 1486                 if (error == ENOENT || error == EDEADLK) {
 1487                         if (hammer_debug_general & 0x2000) {
 1488                                 kprintf("error %d node %p %016llx index %d\n",
 1489                                         error, cursor->node,
 1490                                         (long long)cursor->node->node_offset,
 1491                                         cursor->index);
 1492                         }
 1493                         cursor->flags &= ~HAMMER_CURSOR_ATEDISK;
 1494                         error = hammer_btree_iterate(cursor);
 1495                 }
 1496                 if (error == 0) {
 1497                         cursor->flags &= ~(HAMMER_CURSOR_DISKEOF |
 1498                                            HAMMER_CURSOR_ATEDISK);
 1499                 } else {
 1500                         cursor->flags |= HAMMER_CURSOR_DISKEOF |
 1501                                          HAMMER_CURSOR_ATEDISK;
 1502                         if (error == ENOENT)
 1503                                 error = 0;
 1504                 }
 1505         } else {
 1506                 cursor->flags |= HAMMER_CURSOR_DISKEOF | HAMMER_CURSOR_ATEDISK;
 1507                 error = 0;
 1508         }
 1509         return(error);
 1510 }
 1511 
 1512 /*
 1513  * Helper for hammer_ip_next()
 1514  *
 1515  * The caller has determined that the media cursor is further along than the
 1516  * memory cursor and must be reseeked after a generation number change.
 1517  */
 1518 static
 1519 int
 1520 _hammer_ip_reseek(hammer_cursor_t cursor)
 1521 {
 1522         struct hammer_base_elm save;
 1523         hammer_btree_elm_t elm;
 1524         int error __debugvar;
 1525         int r;
 1526         int again = 0;
 1527 
 1528         /*
 1529          * Do the re-seek.
 1530          */
 1531         kprintf("HAMMER: Debug: re-seeked during scan @ino=%016llx\n",
 1532                 (long long)cursor->ip->obj_id);
 1533         save = cursor->key_beg;
 1534         cursor->key_beg = cursor->iprec->leaf.base;
 1535         error = _hammer_ip_seek_btree(cursor);
 1536         KKASSERT(error == 0);
 1537         cursor->key_beg = save;
 1538 
 1539         /*
 1540          * If the memory record was previous returned to
 1541          * the caller and the media record matches
 1542          * (-1/+1: only create_tid differs), then iterate
 1543          * the media record to avoid a double result.
 1544          */
 1545         if ((cursor->flags & HAMMER_CURSOR_ATEDISK) == 0 &&
 1546             (cursor->flags & HAMMER_CURSOR_LASTWASMEM)) {
 1547                 elm = &cursor->node->ondisk->elms[cursor->index];
 1548                 r = hammer_btree_cmp(&elm->base,
 1549                                      &cursor->iprec->leaf.base);
 1550                 if (cursor->flags & HAMMER_CURSOR_ASOF) {
 1551                         if (r >= -1 && r <= 1) {
 1552                                 kprintf("HAMMER: Debug: iterated after "
 1553                                         "re-seek (asof r=%d)\n", r);
 1554                                 cursor->flags |= HAMMER_CURSOR_ATEDISK;
 1555                                 again = 1;
 1556                         }
 1557                 } else {
 1558                         if (r == 0) {
 1559                                 kprintf("HAMMER: Debug: iterated after "
 1560                                         "re-seek\n");
 1561                                 cursor->flags |= HAMMER_CURSOR_ATEDISK;
 1562                                 again = 1;
 1563                         }
 1564                 }
 1565         }
 1566         return(again);
 1567 }
 1568 
 1569 /*
 1570  * Locate the first record within the cursor's key_beg/key_end range,
 1571  * restricted to a particular inode.  0 is returned on success, ENOENT
 1572  * if no records matched the requested range, or some other error.
 1573  *
 1574  * When 0 is returned hammer_ip_next() may be used to iterate additional
 1575  * records within the requested range.
 1576  *
 1577  * This function can return EDEADLK, requiring the caller to terminate
 1578  * the cursor and try again.
 1579  */
 1580 
 1581 int
 1582 hammer_ip_first(hammer_cursor_t cursor)
 1583 {
 1584         hammer_inode_t ip __debugvar = cursor->ip;
 1585         int error;
 1586 
 1587         KKASSERT(ip != NULL);
 1588 
 1589         /*
 1590          * Clean up fields and setup for merged scan
 1591          */
 1592         cursor->flags &= ~HAMMER_CURSOR_RETEST;
 1593 
 1594         /*
 1595          * Search the in-memory record list (Red-Black tree).  Unlike the
 1596          * B-Tree search, mem_first checks for records in the range.
 1597          *
 1598          * This function will setup both ATEMEM and MEMEOF properly for
 1599          * the ip iteration.  ATEMEM will be set if MEMEOF is set.
 1600          */
 1601         hammer_mem_first(cursor);
 1602 
 1603         /*
 1604          * Detect generation changes during blockages, including
 1605          * blockages which occur on the initial btree search.
 1606          */
 1607         cursor->rec_generation = cursor->ip->rec_generation;
 1608 
 1609         /*
 1610          * Initial search and result
 1611          */
 1612         error = _hammer_ip_seek_btree(cursor);
 1613         if (error == 0)
 1614                 error = hammer_ip_next(cursor);
 1615 
 1616         return (error);
 1617 }
 1618 
 1619 /*
 1620  * Retrieve the next record in a merged iteration within the bounds of the
 1621  * cursor.  This call may be made multiple times after the cursor has been
 1622  * initially searched with hammer_ip_first().
 1623  *
 1624  * There are numerous special cases in this code to deal with races between
 1625  * in-memory records and on-media records.
 1626  *
 1627  * 0 is returned on success, ENOENT if no further records match the
 1628  * requested range, or some other error code is returned.
 1629  */
 1630 int
 1631 hammer_ip_next(hammer_cursor_t cursor)
 1632 {
 1633         hammer_btree_elm_t elm;
 1634         hammer_record_t rec;
 1635         hammer_record_t tmprec;
 1636         int error;
 1637         int r;
 1638 
 1639 again:
 1640         /*
 1641          * Get the next on-disk record
 1642          *
 1643          * NOTE: If we deleted the last on-disk record we had scanned
 1644          *       ATEDISK will be clear and RETEST will be set, forcing
 1645          *       a call to iterate.  The fact that ATEDISK is clear causes
 1646          *       iterate to re-test the 'current' element.  If ATEDISK is
 1647          *       set, iterate will skip the 'current' element.
 1648          */
 1649         error = 0;
 1650         if ((cursor->flags & HAMMER_CURSOR_DISKEOF) == 0) {
 1651                 if (cursor->flags & (HAMMER_CURSOR_ATEDISK |
 1652                                      HAMMER_CURSOR_RETEST)) {
 1653                         error = hammer_btree_iterate(cursor);
 1654                         cursor->flags &= ~HAMMER_CURSOR_RETEST;
 1655                         if (error == 0) {
 1656                                 cursor->flags &= ~HAMMER_CURSOR_ATEDISK;
 1657                                 hammer_cache_node(&cursor->ip->cache[1],
 1658                                                   cursor->node);
 1659                         } else if (error == ENOENT) {
 1660                                 cursor->flags |= HAMMER_CURSOR_DISKEOF |
 1661                                                  HAMMER_CURSOR_ATEDISK;
 1662                                 error = 0;
 1663                         }
 1664                 }
 1665         }
 1666 
 1667         /*
 1668          * If the generation changed the backend has deleted or committed
 1669          * one or more memory records since our last check.
 1670          *
 1671          * When this case occurs if the disk cursor is > current memory record
 1672          * or the disk cursor is at EOF, we must re-seek the disk-cursor.
 1673          * Since the cursor is ahead it must have not yet been eaten (if
 1674          * not at eof anyway). (XXX data offset case?)
 1675          *
 1676          * NOTE: we are not doing a full check here.  That will be handled
 1677          * later on.
 1678          *
 1679          * If we have exhausted all memory records we do not have to do any
 1680          * further seeks.
 1681          */
 1682         while (cursor->rec_generation != cursor->ip->rec_generation &&
 1683                error == 0
 1684         ) {
 1685                 kprintf("HAMMER: Debug: generation changed during scan @ino=%016llx\n", (long long)cursor->ip->obj_id);
 1686                 cursor->rec_generation = cursor->ip->rec_generation;
 1687                 if (cursor->flags & HAMMER_CURSOR_MEMEOF)
 1688                         break;
 1689                 if (cursor->flags & HAMMER_CURSOR_DISKEOF) {
 1690                         r = 1;
 1691                 } else {
 1692                         KKASSERT((cursor->flags & HAMMER_CURSOR_ATEDISK) == 0);
 1693                         elm = &cursor->node->ondisk->elms[cursor->index];
 1694                         r = hammer_btree_cmp(&elm->base,
 1695                                              &cursor->iprec->leaf.base);
 1696                 }
 1697 
 1698                 /*
 1699                  * Do we re-seek the media cursor?
 1700                  */
 1701                 if (r > 0) {
 1702                         if (_hammer_ip_reseek(cursor))
 1703                                 goto again;
 1704                 }
 1705         }
 1706 
 1707         /*
 1708          * We can now safely get the next in-memory record.  We cannot
 1709          * block here.
 1710          *
 1711          * hammer_rec_scan_cmp:  Is the record still in our general range,
 1712          *                       (non-inclusive of snapshot exclusions)?
 1713          * hammer_rec_scan_callback: Is the record in our snapshot?
 1714          */
 1715         tmprec = NULL;
 1716         if ((cursor->flags & HAMMER_CURSOR_MEMEOF) == 0) {
 1717                 /*
 1718                  * If the current memory record was eaten then get the next
 1719                  * one.  Stale records are skipped.
 1720                  */
 1721                 if (cursor->flags & HAMMER_CURSOR_ATEMEM) {
 1722                         tmprec = cursor->iprec;
 1723                         cursor->iprec = NULL;
 1724                         rec = hammer_rec_rb_tree_RB_NEXT(tmprec);
 1725                         while (rec) {
 1726                                 if (hammer_rec_scan_cmp(rec, cursor) != 0)
 1727                                         break;
 1728                                 if (hammer_rec_scan_callback(rec, cursor) != 0)
 1729                                         break;
 1730                                 rec = hammer_rec_rb_tree_RB_NEXT(rec);
 1731                         }
 1732                         if (cursor->iprec) {
 1733                                 KKASSERT(cursor->iprec == rec);
 1734                                 cursor->flags &= ~HAMMER_CURSOR_ATEMEM;
 1735                         } else {
 1736                                 cursor->flags |= HAMMER_CURSOR_MEMEOF;
 1737                         }
 1738                         cursor->flags &= ~HAMMER_CURSOR_LASTWASMEM;
 1739                 }
 1740         }
 1741 
 1742         /*
 1743          * MEMORY RECORD VALIDITY TEST
 1744          *
 1745          * (We still can't block, which is why tmprec is being held so
 1746          * long).
 1747          *
 1748          * If the memory record is no longer valid we skip it.  It may
 1749          * have been deleted by the frontend.  If it was deleted or
 1750          * committed by the backend the generation change re-seeked the
 1751          * disk cursor and the record will be present there.
 1752          */
 1753         if (error == 0 && (cursor->flags & HAMMER_CURSOR_MEMEOF) == 0) {
 1754                 KKASSERT(cursor->iprec);
 1755                 KKASSERT((cursor->flags & HAMMER_CURSOR_ATEMEM) == 0);
 1756                 if (!hammer_ip_iterate_mem_good(cursor, cursor->iprec)) {
 1757                         cursor->flags |= HAMMER_CURSOR_ATEMEM;
 1758                         if (tmprec)
 1759                                 hammer_rel_mem_record(tmprec);
 1760                         goto again;
 1761                 }
 1762         }
 1763         if (tmprec)
 1764                 hammer_rel_mem_record(tmprec);
 1765 
 1766         /*
 1767          * Extract either the disk or memory record depending on their
 1768          * relative position.
 1769          */
 1770         error = 0;
 1771         switch(cursor->flags & (HAMMER_CURSOR_ATEDISK | HAMMER_CURSOR_ATEMEM)) {
 1772         case 0:
 1773                 /*
 1774                  * Both entries valid.   Compare the entries and nominally
 1775                  * return the first one in the sort order.  Numerous cases
 1776                  * require special attention, however.
 1777                  */
 1778                 elm = &cursor->node->ondisk->elms[cursor->index];
 1779                 r = hammer_btree_cmp(&elm->base, &cursor->iprec->leaf.base);
 1780 
 1781                 /*
 1782                  * If the two entries differ only by their key (-2/2) or
 1783                  * create_tid (-1/1), and are DATA records, we may have a
 1784                  * nominal match.  We have to calculate the base file
 1785                  * offset of the data.
 1786                  */
 1787                 if (r <= 2 && r >= -2 && r != 0 &&
 1788                     cursor->ip->ino_data.obj_type == HAMMER_OBJTYPE_REGFILE &&
 1789                     cursor->iprec->type == HAMMER_MEM_RECORD_DATA) {
 1790                         int64_t base1 = elm->leaf.base.key - elm->leaf.data_len;
 1791                         int64_t base2 = cursor->iprec->leaf.base.key -
 1792                                         cursor->iprec->leaf.data_len;
 1793                         if (base1 == base2)
 1794                                 r = 0;
 1795                 }
 1796 
 1797                 if (r < 0) {
 1798                         error = hammer_btree_extract(cursor,
 1799                                                      HAMMER_CURSOR_GET_LEAF);
 1800                         cursor->flags |= HAMMER_CURSOR_ATEDISK;
 1801                         cursor->flags &= ~HAMMER_CURSOR_LASTWASMEM;
 1802                         break;
 1803                 }
 1804 
 1805                 /*
 1806                  * If the entries match exactly the memory entry is either
 1807                  * an on-disk directory entry deletion or a bulk data
 1808                  * overwrite.  If it is a directory entry deletion we eat
 1809                  * both entries.
 1810                  *
 1811                  * For the bulk-data overwrite case it is possible to have
 1812                  * visibility into both, which simply means the syncer
 1813                  * hasn't gotten around to doing the delete+insert sequence
 1814                  * on the B-Tree.  Use the memory entry and throw away the
 1815                  * on-disk entry.
 1816                  *
 1817                  * If the in-memory record is not either of these we
 1818                  * probably caught the syncer while it was syncing it to
 1819                  * the media.  Since we hold a shared lock on the cursor,
 1820                  * the in-memory record had better be marked deleted at
 1821                  * this point.
 1822                  */
 1823                 if (r == 0) {
 1824                         if (cursor->iprec->type == HAMMER_MEM_RECORD_DEL) {
 1825                                 if ((cursor->flags & HAMMER_CURSOR_DELETE_VISIBILITY) == 0) {
 1826                                         cursor->flags |= HAMMER_CURSOR_ATEDISK;
 1827                                         cursor->flags |= HAMMER_CURSOR_ATEMEM;
 1828                                         goto again;
 1829                                 }
 1830                         } else if (cursor->iprec->type == HAMMER_MEM_RECORD_DATA) {
 1831                                 if ((cursor->flags & HAMMER_CURSOR_DELETE_VISIBILITY) == 0) {
 1832                                         cursor->flags |= HAMMER_CURSOR_ATEDISK;
 1833                                 }
 1834                                 /* fall through to memory entry */
 1835                         } else {
 1836                                 panic("hammer_ip_next: duplicate mem/b-tree entry %p %d %08x", cursor->iprec, cursor->iprec->type, cursor->iprec->flags);
 1837                                 cursor->flags |= HAMMER_CURSOR_ATEMEM;
 1838                                 goto again;
 1839                         }
 1840                 }
 1841                 /* fall through to the memory entry */
 1842         case HAMMER_CURSOR_ATEDISK:
 1843                 /*
 1844                  * Only the memory entry is valid.
 1845                  */
 1846                 cursor->leaf = &cursor->iprec->leaf;
 1847                 cursor->flags |= HAMMER_CURSOR_ATEMEM;
 1848                 cursor->flags |= HAMMER_CURSOR_LASTWASMEM;
 1849 
 1850                 /*
 1851                  * If the memory entry is an on-disk deletion we should have
 1852                  * also had found a B-Tree record.  If the backend beat us
 1853                  * to it it would have interlocked the cursor and we should
 1854                  * have seen the in-memory record marked DELETED_FE.
 1855                  */
 1856                 if (cursor->iprec->type == HAMMER_MEM_RECORD_DEL &&
 1857                     (cursor->flags & HAMMER_CURSOR_DELETE_VISIBILITY) == 0) {
 1858                         panic("hammer_ip_next: del-on-disk with no b-tree entry iprec %p flags %08x", cursor->iprec, cursor->iprec->flags);
 1859                 }
 1860                 break;
 1861         case HAMMER_CURSOR_ATEMEM:
 1862                 /*
 1863                  * Only the disk entry is valid
 1864                  */
 1865                 error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_LEAF);
 1866                 cursor->flags |= HAMMER_CURSOR_ATEDISK;
 1867                 cursor->flags &= ~HAMMER_CURSOR_LASTWASMEM;
 1868                 break;
 1869         default:
 1870                 /*
 1871                  * Neither entry is valid
 1872                  *
 1873                  * XXX error not set properly
 1874                  */
 1875                 cursor->flags &= ~HAMMER_CURSOR_LASTWASMEM;
 1876                 cursor->leaf = NULL;
 1877                 error = ENOENT;
 1878                 break;
 1879         }
 1880         return(error);
 1881 }
 1882 
 1883 /*
 1884  * Resolve the cursor->data pointer for the current cursor position in
 1885  * a merged iteration.
 1886  */
 1887 int
 1888 hammer_ip_resolve_data(hammer_cursor_t cursor)
 1889 {
 1890         hammer_record_t record;
 1891         int error;
 1892 
 1893         if (hammer_cursor_inmem(cursor)) {
 1894                 /*
 1895                  * The data associated with an in-memory record is usually
 1896                  * kmalloced, but reserve-ahead data records will have an
 1897                  * on-disk reference.
 1898                  *
 1899                  * NOTE: Reserve-ahead data records must be handled in the
 1900                  * context of the related high level buffer cache buffer
 1901                  * to interlock against async writes.
 1902                  */
 1903                 record = cursor->iprec;
 1904                 cursor->data = record->data;
 1905                 error = 0;
 1906                 if (cursor->data == NULL) {
 1907                         KKASSERT(record->leaf.base.rec_type ==
 1908                                  HAMMER_RECTYPE_DATA);
 1909                         cursor->data = hammer_bread_ext(cursor->trans->hmp,
 1910                                                     record->leaf.data_offset,
 1911                                                     record->leaf.data_len,
 1912                                                     &error,
 1913                                                     &cursor->data_buffer);
 1914                 }
 1915         } else {
 1916                 cursor->leaf = &cursor->node->ondisk->elms[cursor->index].leaf;
 1917                 error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_DATA);
 1918         }
 1919         return(error);
 1920 }
 1921 
 1922 /*
 1923  * Backend truncation / record replacement - delete records in range.
 1924  *
 1925  * Delete all records within the specified range for inode ip.  In-memory
 1926  * records still associated with the frontend are ignored. 
 1927  *
 1928  * If truncating is non-zero in-memory records associated with the back-end
 1929  * are ignored.  If truncating is > 1 we can return EWOULDBLOCK.
 1930  *
 1931  * NOTES:
 1932  *
 1933  *      * An unaligned range will cause new records to be added to cover
 1934  *        the edge cases. (XXX not implemented yet).
 1935  *
 1936  *      * Replacement via reservations (see hammer_ip_sync_record_cursor())
 1937  *        also do not deal with unaligned ranges.
 1938  *
 1939  *      * ran_end is inclusive (e.g. 0,1023 instead of 0,1024).
 1940  *
 1941  *      * Record keys for regular file data have to be special-cased since
 1942  *        they indicate the end of the range (key = base + bytes).
 1943  *
 1944  *      * This function may be asked to delete ridiculously huge ranges, for
 1945  *        example if someone truncates or removes a 1TB regular file.  We
 1946  *        must be very careful on restarts and we may have to stop w/
 1947  *        EWOULDBLOCK to avoid blowing out the buffer cache.
 1948  */
 1949 int
 1950 hammer_ip_delete_range(hammer_cursor_t cursor, hammer_inode_t ip,
 1951                        int64_t ran_beg, int64_t ran_end, int truncating)
 1952 {
 1953         hammer_transaction_t trans = cursor->trans;
 1954         hammer_btree_leaf_elm_t leaf;
 1955         int error;
 1956         int64_t off;
 1957         int64_t tmp64;
 1958 
 1959 #if 0
 1960         kprintf("delete_range %p %016llx-%016llx\n", ip, ran_beg, ran_end);
 1961 #endif
 1962 
 1963         KKASSERT(trans->type == HAMMER_TRANS_FLS);
 1964 retry:
 1965         hammer_normalize_cursor(cursor);
 1966         cursor->key_beg.localization = ip->obj_localization +
 1967                                        HAMMER_LOCALIZE_MISC;
 1968         cursor->key_beg.obj_id = ip->obj_id;
 1969         cursor->key_beg.create_tid = 0;
 1970         cursor->key_beg.delete_tid = 0;
 1971         cursor->key_beg.obj_type = 0;
 1972 
 1973         if (ip->ino_data.obj_type == HAMMER_OBJTYPE_DBFILE) {
 1974                 cursor->key_beg.key = ran_beg;
 1975                 cursor->key_beg.rec_type = HAMMER_RECTYPE_DB;
 1976         } else {
 1977                 /*
 1978                  * The key in the B-Tree is (base+bytes), so the first possible
 1979                  * matching key is ran_beg + 1.
 1980                  */
 1981                 cursor->key_beg.key = ran_beg + 1;
 1982                 cursor->key_beg.rec_type = HAMMER_RECTYPE_DATA;
 1983         }
 1984 
 1985         cursor->key_end = cursor->key_beg;
 1986         if (ip->ino_data.obj_type == HAMMER_OBJTYPE_DBFILE) {
 1987                 cursor->key_end.key = ran_end;
 1988         } else {
 1989                 tmp64 = ran_end + MAXPHYS + 1;  /* work around GCC-4 bug */
 1990                 if (tmp64 < ran_end)
 1991                         cursor->key_end.key = 0x7FFFFFFFFFFFFFFFLL;
 1992                 else
 1993                         cursor->key_end.key = ran_end + MAXPHYS + 1;
 1994         }
 1995 
 1996         cursor->asof = ip->obj_asof;
 1997         cursor->flags &= ~HAMMER_CURSOR_INITMASK;
 1998         cursor->flags |= HAMMER_CURSOR_ASOF;
 1999         cursor->flags |= HAMMER_CURSOR_DELETE_VISIBILITY;
 2000         cursor->flags |= HAMMER_CURSOR_BACKEND;
 2001         cursor->flags |= HAMMER_CURSOR_END_INCLUSIVE;
 2002 
 2003         error = hammer_ip_first(cursor);
 2004 
 2005         /*
 2006          * Iterate through matching records and mark them as deleted.
 2007          */
 2008         while (error == 0) {
 2009                 leaf = cursor->leaf;
 2010 
 2011                 KKASSERT(leaf->base.delete_tid == 0);
 2012                 KKASSERT(leaf->base.obj_id == ip->obj_id);
 2013 
 2014                 /*
 2015                  * There may be overlap cases for regular file data.  Also
 2016                  * remember the key for a regular file record is (base + len),
 2017                  * NOT (base).
 2018                  *
 2019                  * Note that due to duplicates (mem & media) allowed by
 2020                  * DELETE_VISIBILITY, off can wind up less then ran_beg.
 2021                  */
 2022                 if (leaf->base.rec_type == HAMMER_RECTYPE_DATA) {
 2023                         off = leaf->base.key - leaf->data_len;
 2024                         /*
 2025                          * Check the left edge case.  We currently do not
 2026                          * split existing records.
 2027                          */
 2028                         if (off < ran_beg && leaf->base.key > ran_beg) {
 2029                                 panic("hammer left edge case %016llx %d",
 2030                                         (long long)leaf->base.key,
 2031                                         leaf->data_len);
 2032                         }
 2033 
 2034                         /*
 2035                          * Check the right edge case.  Note that the
 2036                          * record can be completely out of bounds, which
 2037                          * terminates the search.
 2038                          *
 2039                          * base->key is exclusive of the right edge while
 2040                          * ran_end is inclusive of the right edge.  The
 2041                          * (key - data_len) left boundary is inclusive.
 2042                          *
 2043                          * XXX theory-check this test at some point, are
 2044                          * we missing a + 1 somewhere?  Note that ran_end
 2045                          * could overflow.
 2046                          */
 2047                         if (leaf->base.key - 1 > ran_end) {
 2048                                 if (leaf->base.key - leaf->data_len > ran_end)
 2049                                         break;
 2050                                 panic("hammer right edge case");
 2051                         }
 2052                 } else {
 2053                         off = leaf->base.key;
 2054                 }
 2055 
 2056                 /*
 2057                  * Delete the record.  When truncating we do not delete
 2058                  * in-memory (data) records because they represent data
 2059                  * written after the truncation.
 2060                  *
 2061                  * This will also physically destroy the B-Tree entry and
 2062                  * data if the retention policy dictates.  The function
 2063                  * will set HAMMER_CURSOR_RETEST to cause hammer_ip_next()
 2064                  * to retest the new 'current' element.
 2065                  */
 2066                 if (truncating == 0 || hammer_cursor_ondisk(cursor)) {
 2067                         error = hammer_ip_delete_record(cursor, ip, trans->tid);
 2068                         /*
 2069                          * If we have built up too many meta-buffers we risk
 2070                          * deadlocking the kernel and must stop.  This can
 2071                          * occur when deleting ridiculously huge files.
 2072                          * sync_trunc_off is updated so the next cycle does
 2073                          * not re-iterate records we have already deleted.
 2074                          *
 2075                          * This is only done with formal truncations.
 2076                          */
 2077                         if (truncating > 1 && error == 0 &&
 2078                             hammer_flusher_meta_limit(ip->hmp)) {
 2079                                 ip->sync_trunc_off = off;
 2080                                 error = EWOULDBLOCK;
 2081                         }
 2082                 }
 2083                 if (error)
 2084                         break;
 2085                 ran_beg = off;  /* for restart */
 2086                 error = hammer_ip_next(cursor);
 2087         }
 2088         if (cursor->node)
 2089                 hammer_cache_node(&ip->cache[1], cursor->node);
 2090 
 2091         if (error == EDEADLK) {
 2092                 hammer_done_cursor(cursor);
 2093                 error = hammer_init_cursor(trans, cursor, &ip->cache[1], ip);
 2094                 if (error == 0)
 2095                         goto retry;
 2096         }
 2097         if (error == ENOENT)
 2098                 error = 0;
 2099         return(error);
 2100 }
 2101 
 2102 /*
 2103  * This backend function deletes the specified record on-disk, similar to
 2104  * delete_range but for a specific record.  Unlike the exact deletions
 2105  * used when deleting a directory entry this function uses an ASOF search 
 2106  * like delete_range.
 2107  *
 2108  * This function may be called with ip->obj_asof set for a slave snapshot,
 2109  * so don't use it.  We always delete non-historical records only.
 2110  */
 2111 static int
 2112 hammer_delete_general(hammer_cursor_t cursor, hammer_inode_t ip,
 2113                       hammer_btree_leaf_elm_t leaf)
 2114 {
 2115         hammer_transaction_t trans = cursor->trans;
 2116         int error;
 2117 
 2118         KKASSERT(trans->type == HAMMER_TRANS_FLS);
 2119 retry:
 2120         hammer_normalize_cursor(cursor);
 2121         cursor->key_beg = leaf->base;
 2122         cursor->asof = HAMMER_MAX_TID;
 2123         cursor->flags &= ~HAMMER_CURSOR_INITMASK;
 2124         cursor->flags |= HAMMER_CURSOR_ASOF;
 2125         cursor->flags |= HAMMER_CURSOR_BACKEND;
 2126         cursor->flags &= ~HAMMER_CURSOR_INSERT;
 2127 
 2128         error = hammer_btree_lookup(cursor);
 2129         if (error == 0) {
 2130                 error = hammer_ip_delete_record(cursor, ip, trans->tid);
 2131         }
 2132         if (error == EDEADLK) {
 2133                 hammer_done_cursor(cursor);
 2134                 error = hammer_init_cursor(trans, cursor, &ip->cache[1], ip);
 2135                 if (error == 0)
 2136                         goto retry;
 2137         }
 2138         return(error);
 2139 }
 2140 
 2141 /*
 2142  * This function deletes remaining auxillary records when an inode is
 2143  * being deleted.  This function explicitly does not delete the
 2144  * inode record, directory entry, data, or db records.  Those must be
 2145  * properly disposed of prior to this call.
 2146  */
 2147 int
 2148 hammer_ip_delete_clean(hammer_cursor_t cursor, hammer_inode_t ip, int *countp)
 2149 {
 2150         hammer_transaction_t trans = cursor->trans;
 2151         hammer_btree_leaf_elm_t leaf __debugvar;
 2152         int error;
 2153 
 2154         KKASSERT(trans->type == HAMMER_TRANS_FLS);
 2155 retry:
 2156         hammer_normalize_cursor(cursor);
 2157         cursor->key_beg.localization = ip->obj_localization +
 2158                                        HAMMER_LOCALIZE_MISC;
 2159         cursor->key_beg.obj_id = ip->obj_id;
 2160         cursor->key_beg.create_tid = 0;
 2161         cursor->key_beg.delete_tid = 0;
 2162         cursor->key_beg.obj_type = 0;
 2163         cursor->key_beg.rec_type = HAMMER_RECTYPE_CLEAN_START;
 2164         cursor->key_beg.key = HAMMER_MIN_KEY;
 2165 
 2166         cursor->key_end = cursor->key_beg;
 2167         cursor->key_end.rec_type = HAMMER_RECTYPE_MAX;
 2168         cursor->key_end.key = HAMMER_MAX_KEY;
 2169 
 2170         cursor->asof = ip->obj_asof;
 2171         cursor->flags &= ~HAMMER_CURSOR_INITMASK;
 2172         cursor->flags |= HAMMER_CURSOR_END_INCLUSIVE | HAMMER_CURSOR_ASOF;
 2173         cursor->flags |= HAMMER_CURSOR_DELETE_VISIBILITY;
 2174         cursor->flags |= HAMMER_CURSOR_BACKEND;
 2175 
 2176         error = hammer_ip_first(cursor);
 2177 
 2178         /*
 2179          * Iterate through matching records and mark them as deleted.
 2180          */
 2181         while (error == 0) {
 2182                 leaf = cursor->leaf;
 2183 
 2184                 KKASSERT(leaf->base.delete_tid == 0);
 2185 
 2186                 /*
 2187                  * Mark the record and B-Tree entry as deleted.  This will
 2188                  * also physically delete the B-Tree entry, record, and
 2189                  * data if the retention policy dictates.  The function
 2190                  * will set HAMMER_CURSOR_RETEST to cause hammer_ip_next()
 2191                  * to retest the new 'current' element.
 2192                  *
 2193                  * Directory entries (and delete-on-disk directory entries)
 2194                  * must be synced and cannot be deleted.
 2195                  */
 2196                 error = hammer_ip_delete_record(cursor, ip, trans->tid);
 2197                 ++*countp;
 2198                 if (error)
 2199                         break;
 2200                 error = hammer_ip_next(cursor);
 2201         }
 2202         if (cursor->node)
 2203                 hammer_cache_node(&ip->cache[1], cursor->node);
 2204         if (error == EDEADLK) {
 2205                 hammer_done_cursor(cursor);
 2206                 error = hammer_init_cursor(trans, cursor, &ip->cache[1], ip);
 2207                 if (error == 0)
 2208                         goto retry;
 2209         }
 2210         if (error == ENOENT)
 2211                 error = 0;
 2212         return(error);
 2213 }
 2214 
 2215 /*
 2216  * Delete the record at the current cursor.  On success the cursor will
 2217  * be positioned appropriately for an iteration but may no longer be at
 2218  * a leaf node.
 2219  *
 2220  * This routine is only called from the backend.
 2221  *
 2222  * NOTE: This can return EDEADLK, requiring the caller to terminate the
 2223  * cursor and retry.
 2224  */
 2225 int
 2226 hammer_ip_delete_record(hammer_cursor_t cursor, hammer_inode_t ip,
 2227                         hammer_tid_t tid)
 2228 {
 2229         hammer_record_t iprec;
 2230         int error;
 2231 
 2232         KKASSERT(cursor->flags & HAMMER_CURSOR_BACKEND);
 2233         KKASSERT(tid != 0);
 2234 
 2235         /*
 2236          * In-memory (unsynchronized) records can simply be freed.  This
 2237          * only occurs in range iterations since all other records are
 2238          * individually synchronized.  Thus there should be no confusion with
 2239          * the interlock.
 2240          *
 2241          * An in-memory record may be deleted before being committed to disk,
 2242          * but could have been accessed in the mean time.  The reservation
 2243          * code will deal with the case.
 2244          */
 2245         if (hammer_cursor_inmem(cursor)) {
 2246                 iprec = cursor->iprec;
 2247                 KKASSERT((iprec->flags & HAMMER_RECF_INTERLOCK_BE) ==0);
 2248                 iprec->flags |= HAMMER_RECF_DELETED_FE;
 2249                 iprec->flags |= HAMMER_RECF_DELETED_BE;
 2250                 KKASSERT(iprec->ip == ip);
 2251                 ++ip->rec_generation;
 2252                 return(0);
 2253         }
 2254 
 2255         /*
 2256          * On-disk records are marked as deleted by updating their delete_tid.
 2257          * This does not effect their position in the B-Tree (which is based
 2258          * on their create_tid).
 2259          *
 2260          * Frontend B-Tree operations track inodes so we tell 
 2261          * hammer_delete_at_cursor() not to.
 2262          */
 2263         error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_LEAF);
 2264 
 2265         if (error == 0) {
 2266                 error = hammer_delete_at_cursor(
 2267                                 cursor,
 2268                                 HAMMER_DELETE_ADJUST | hammer_nohistory(ip),
 2269                                 cursor->trans->tid,
 2270                                 cursor->trans->time32,
 2271                                 0, NULL);
 2272         }
 2273         return(error);
 2274 }
 2275 
 2276 /*
 2277  * Used to write a generic record w/optional data to the media b-tree
 2278  * when no inode context is available.  Used by the mirroring and
 2279  * snapshot code.
 2280  *
 2281  * Caller must set cursor->key_beg to leaf->base.  The cursor must be
 2282  * flagged for backend operation and not flagged ASOF (since we are
 2283  * doing an insertion).
 2284  *
 2285  * This function will acquire the appropriate sync lock and will set
 2286  * the cursor insertion flag for the operation, do the btree lookup,
 2287  * and the insertion, and clear the insertion flag and sync lock before
 2288  * returning.  The cursor state will be such that the caller can continue
 2289  * scanning (used by the mirroring code).
 2290  *
 2291  * mode: HAMMER_CREATE_MODE_UMIRROR     copyin data, check crc
 2292  *       HAMMER_CREATE_MODE_SYS         bcopy data, generate crc
 2293  *
 2294  * NOTE: EDEADLK can be returned.  The caller must do deadlock handling and
 2295  *                retry.
 2296  *
 2297  *       EALREADY can be returned if the record already exists (WARNING,
 2298  *                because ASOF cannot be used no check is made for illegal
 2299  *                duplicates).
 2300  *
 2301  * NOTE: Do not use the function for normal inode-related records as this
 2302  *       functions goes directly to the media and is not integrated with
 2303  *       in-memory records.
 2304  */
 2305 int
 2306 hammer_create_at_cursor(hammer_cursor_t cursor, hammer_btree_leaf_elm_t leaf,
 2307                         void *udata, int mode)
 2308 {
 2309         hammer_transaction_t trans;
 2310         hammer_buffer_t data_buffer;
 2311         hammer_off_t ndata_offset;
 2312         hammer_tid_t high_tid;
 2313         void *ndata;
 2314         int error;
 2315         int doprop;
 2316 
 2317         trans = cursor->trans;
 2318         data_buffer = NULL;
 2319         ndata_offset = 0;
 2320         doprop = 0;
 2321 
 2322         KKASSERT((cursor->flags &
 2323                   (HAMMER_CURSOR_BACKEND | HAMMER_CURSOR_ASOF)) ==
 2324                   (HAMMER_CURSOR_BACKEND));
 2325 
 2326         hammer_sync_lock_sh(trans);
 2327 
 2328         if (leaf->data_len) {
 2329                 ndata = hammer_alloc_data(trans, leaf->data_len,
 2330                                           leaf->base.rec_type,
 2331                                           &ndata_offset, &data_buffer,
 2332                                           0, &error);
 2333                 if (ndata == NULL) {
 2334                         hammer_sync_unlock(trans);
 2335                         return (error);
 2336                 }
 2337                 leaf->data_offset = ndata_offset;
 2338                 hammer_modify_buffer(trans, data_buffer, NULL, 0);
 2339 
 2340                 switch(mode) {
 2341                 case HAMMER_CREATE_MODE_UMIRROR:
 2342                         error = copyin(udata, ndata, leaf->data_len);
 2343                         if (error == 0) {
 2344                                 if (hammer_crc_test_leaf(ndata, leaf) == 0) {
 2345                                         kprintf("data crc mismatch on pipe\n");
 2346                                         error = EINVAL;
 2347                                 } else {
 2348                                         error = hammer_cursor_localize_data(
 2349                                                         ndata, leaf);
 2350                                 }
 2351                         }
 2352                         break;
 2353                 case HAMMER_CREATE_MODE_SYS:
 2354                         bcopy(udata, ndata, leaf->data_len);
 2355                         error = 0;
 2356                         hammer_crc_set_leaf(ndata, leaf);
 2357                         break;
 2358                 default:
 2359                         panic("hammer: hammer_create_at_cursor: bad mode %d",
 2360                                 mode);
 2361                         break; /* NOT REACHED */
 2362                 }
 2363                 hammer_modify_buffer_done(data_buffer);
 2364         } else {
 2365                 leaf->data_offset = 0;
 2366                 error = 0;
 2367                 ndata = NULL;
 2368         }
 2369         if (error)
 2370                 goto failed;
 2371 
 2372         /*
 2373          * Do the insertion.  This can fail with a EDEADLK or EALREADY
 2374          */
 2375         cursor->flags |= HAMMER_CURSOR_INSERT;
 2376         error = hammer_btree_lookup(cursor);
 2377         if (error != ENOENT) {
 2378                 if (error == 0)
 2379                         error = EALREADY;
 2380                 goto failed;
 2381         }
 2382         error = hammer_btree_insert(cursor, leaf, &doprop);
 2383 
 2384         /*
 2385          * Cursor is left on current element, we want to skip it now.
 2386          * (in case the caller is scanning)
 2387          */
 2388         cursor->flags |= HAMMER_CURSOR_ATEDISK;
 2389         cursor->flags &= ~HAMMER_CURSOR_INSERT;
 2390 
 2391         /*
 2392          * If the insertion happens to be creating (and not just replacing)
 2393          * an inode we have to track it.
 2394          */
 2395         if (error == 0 &&
 2396             leaf->base.rec_type == HAMMER_RECTYPE_INODE &&
 2397             leaf->base.delete_tid == 0) {
 2398                 hammer_modify_volume_field(trans, trans->rootvol,
 2399                                            vol0_stat_inodes);
 2400                 ++trans->hmp->rootvol->ondisk->vol0_stat_inodes;
 2401                 hammer_modify_volume_done(trans->rootvol);
 2402         }
 2403 
 2404         /*
 2405          * vol0_next_tid must track the highest TID stored in the filesystem.
 2406          * We do not need to generate undo for this update.
 2407          */
 2408         high_tid = leaf->base.create_tid;
 2409         if (high_tid < leaf->base.delete_tid)
 2410                 high_tid = leaf->base.delete_tid;
 2411         if (trans->rootvol->ondisk->vol0_next_tid < high_tid) {
 2412                 hammer_modify_volume(trans, trans->rootvol, NULL, 0);
 2413                 trans->rootvol->ondisk->vol0_next_tid = high_tid;
 2414                 hammer_modify_volume_done(trans->rootvol);
 2415         }
 2416 
 2417         /*
 2418          * WARNING!  cursor's leaf pointer may have changed after
 2419          *           do_propagation returns.
 2420          */
 2421         if (error == 0 && doprop)
 2422                 hammer_btree_do_propagation(cursor, NULL, leaf);
 2423 
 2424 failed:
 2425         /*
 2426          * Cleanup
 2427          */
 2428         if (error && leaf->data_offset) {
 2429                 hammer_blockmap_free(trans, leaf->data_offset, leaf->data_len);
 2430 
 2431         }
 2432         hammer_sync_unlock(trans);
 2433         if (data_buffer)
 2434                 hammer_rel_buffer(data_buffer, 0);
 2435         return (error);
 2436 }
 2437 
 2438 /*
 2439  * Delete the B-Tree element at the current cursor and do any necessary
 2440  * mirror propagation.
 2441  *
 2442  * The cursor must be properly positioned for an iteration on return but
 2443  * may be pointing at an internal element.
 2444  *
 2445  * An element can be un-deleted by passing a delete_tid of 0 with
 2446  * HAMMER_DELETE_ADJUST.
 2447  */
 2448 int
 2449 hammer_delete_at_cursor(hammer_cursor_t cursor, int delete_flags,
 2450                         hammer_tid_t delete_tid, u_int32_t delete_ts,
 2451                         int track, int64_t *stat_bytes)
 2452 {
 2453         struct hammer_btree_leaf_elm save_leaf;
 2454         hammer_transaction_t trans;
 2455         hammer_btree_leaf_elm_t leaf;
 2456         hammer_node_t node;
 2457         hammer_btree_elm_t elm;
 2458         hammer_off_t data_offset;
 2459         int32_t data_len;
 2460         int error;
 2461         int icount;
 2462         int doprop;
 2463 
 2464         error = hammer_cursor_upgrade(cursor);
 2465         if (error)
 2466                 return(error);
 2467 
 2468         trans = cursor->trans;
 2469         node = cursor->node;
 2470         elm = &node->ondisk->elms[cursor->index];
 2471         leaf = &elm->leaf;
 2472         KKASSERT(elm->base.btype == HAMMER_BTREE_TYPE_RECORD);
 2473 
 2474         hammer_sync_lock_sh(trans);
 2475         doprop = 0;
 2476         icount = 0;
 2477 
 2478         /*
 2479          * Adjust the delete_tid.  Update the mirror_tid propagation field
 2480          * as well.  delete_tid can be 0 (undelete -- used by mirroring).
 2481          */
 2482         if (delete_flags & HAMMER_DELETE_ADJUST) {
 2483                 if (elm->base.rec_type == HAMMER_RECTYPE_INODE) {
 2484                         if (elm->leaf.base.delete_tid == 0 && delete_tid)
 2485                                 icount = -1;
 2486                         if (elm->leaf.base.delete_tid && delete_tid == 0)
 2487                                 icount = 1;
 2488                 }
 2489 
 2490                 hammer_modify_node(trans, node, elm, sizeof(*elm));
 2491                 elm->leaf.base.delete_tid = delete_tid;
 2492                 elm->leaf.delete_ts = delete_ts;
 2493                 hammer_modify_node_done(node);
 2494 
 2495                 if (elm->leaf.base.delete_tid > node->ondisk->mirror_tid) {
 2496                         hammer_modify_node_field(trans, node, mirror_tid);
 2497                         node->ondisk->mirror_tid = elm->leaf.base.delete_tid;
 2498                         hammer_modify_node_done(node);
 2499                         doprop = 1;
 2500                         if (hammer_debug_general & 0x0002) {
 2501                                 kprintf("delete_at_cursor: propagate %016llx"
 2502                                         " @%016llx\n",
 2503                                         (long long)elm->leaf.base.delete_tid,
 2504                                         (long long)node->node_offset);
 2505                         }
 2506                 }
 2507 
 2508                 /*
 2509                  * Adjust for the iteration.  We have deleted the current
 2510                  * element and want to clear ATEDISK so the iteration does
 2511                  * not skip the element after, which now becomes the current
 2512                  * element.  This element must be re-tested if doing an
 2513                  * iteration, which is handled by the RETEST flag.
 2514                  */
 2515                 if ((cursor->flags & HAMMER_CURSOR_DISKEOF) == 0) {
 2516                         cursor->flags |= HAMMER_CURSOR_RETEST;
 2517                         cursor->flags &= ~HAMMER_CURSOR_ATEDISK;
 2518                 }
 2519 
 2520                 /*
 2521                  * An on-disk record cannot have the same delete_tid
 2522                  * as its create_tid.  In a chain of record updates
 2523                  * this could result in a duplicate record.
 2524                  */
 2525                 KKASSERT(elm->leaf.base.delete_tid !=
 2526                          elm->leaf.base.create_tid);
 2527         }
 2528 
 2529         /*
 2530          * Destroy the B-Tree element if asked (typically if a nohistory
 2531          * file or mount, or when called by the pruning code).
 2532          *
 2533          * Adjust the ATEDISK flag to properly support iterations.
 2534          */
 2535         if (delete_flags & HAMMER_DELETE_DESTROY) {
 2536                 data_offset = elm->leaf.data_offset;
 2537                 data_len = elm->leaf.data_len;
 2538                 if (doprop) {
 2539                         save_leaf = elm->leaf;
 2540                         leaf = &save_leaf;
 2541                 }
 2542                 if (elm->base.rec_type == HAMMER_RECTYPE_INODE &&
 2543                     elm->leaf.base.delete_tid == 0) {
 2544                         icount = -1;
 2545                 }
 2546 
 2547                 error = hammer_btree_delete(cursor);
 2548                 if (error == 0) {
 2549                         /*
 2550                          * The deletion moves the next element (if any) to
 2551                          * the current element position.  We must clear
 2552                          * ATEDISK so this element is not skipped and we
 2553                          * must set RETEST to force any iteration to re-test
 2554                          * the element.
 2555                          */
 2556                         if ((cursor->flags & HAMMER_CURSOR_DISKEOF) == 0) {
 2557                                 cursor->flags |= HAMMER_CURSOR_RETEST;
 2558                                 cursor->flags &= ~HAMMER_CURSOR_ATEDISK;
 2559                         }
 2560                 }
 2561                 if (error == 0) {
 2562                         switch(data_offset & HAMMER_OFF_ZONE_MASK) {
 2563                         case HAMMER_ZONE_LARGE_DATA:
 2564                         case HAMMER_ZONE_SMALL_DATA:
 2565                         case HAMMER_ZONE_META:
 2566                                 hammer_blockmap_free(trans,
 2567                                                      data_offset, data_len);
 2568                                 break;
 2569                         default:
 2570                                 break;
 2571                         }
 2572                 }
 2573         }
 2574 
 2575         /*
 2576          * Track inode count and next_tid.  This is used by the mirroring
 2577          * and PFS code.  icount can be negative, zero, or positive.
 2578          */
 2579         if (error == 0 && track) {
 2580                 if (icount) {
 2581                         hammer_modify_volume_field(trans, trans->rootvol,
 2582                                                    vol0_stat_inodes);
 2583                         trans->rootvol->ondisk->vol0_stat_inodes += icount;
 2584                         hammer_modify_volume_done(trans->rootvol);
 2585                 }
 2586                 if (trans->rootvol->ondisk->vol0_next_tid < delete_tid) {
 2587                         hammer_modify_volume(trans, trans->rootvol, NULL, 0);
 2588                         trans->rootvol->ondisk->vol0_next_tid = delete_tid;
 2589                         hammer_modify_volume_done(trans->rootvol);
 2590                 }
 2591         }
 2592 
 2593         /*
 2594          * mirror_tid propagation occurs if the node's mirror_tid had to be
 2595          * updated while adjusting the delete_tid.
 2596          *
 2597          * This occurs when deleting even in nohistory mode, but does not
 2598          * occur when pruning an already-deleted node.
 2599          *
 2600          * cursor->ip is NULL when called from the pruning, mirroring,
 2601          * and pfs code.  If non-NULL propagation will be conditionalized
 2602          * on whether the PFS is in no-history mode or not.
 2603          *
 2604          * WARNING: cursor's leaf pointer may have changed after do_propagation
 2605          *          returns!
 2606          */
 2607         if (doprop) {
 2608                 if (cursor->ip)
 2609                         hammer_btree_do_propagation(cursor, cursor->ip->pfsm, leaf);
 2610                 else
 2611                         hammer_btree_do_propagation(cursor, NULL, leaf);
 2612         }
 2613         hammer_sync_unlock(trans);
 2614         return (error);
 2615 }
 2616 
 2617 /*
 2618  * Determine whether we can remove a directory.  This routine checks whether
 2619  * a directory is empty or not and enforces flush connectivity.
 2620  *
 2621  * Flush connectivity requires that we block if the target directory is
 2622  * currently flushing, otherwise it may not end up in the same flush group.
 2623  *
 2624  * Returns 0 on success, ENOTEMPTY or EDEADLK (or other errors) on failure.
 2625  */
 2626 int
 2627 hammer_ip_check_directory_empty(hammer_transaction_t trans, hammer_inode_t ip)
 2628 {
 2629         struct hammer_cursor cursor;
 2630         int error;
 2631 
 2632         /*
 2633          * Check directory empty
 2634          */
 2635         hammer_init_cursor(trans, &cursor, &ip->cache[1], ip);
 2636 
 2637         cursor.key_beg.localization = ip->obj_localization +
 2638                                       hammer_dir_localization(ip);
 2639         cursor.key_beg.obj_id = ip->obj_id;
 2640         cursor.key_beg.create_tid = 0;
 2641         cursor.key_beg.delete_tid = 0;
 2642         cursor.key_beg.obj_type = 0;
 2643         cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE + 1;
 2644         cursor.key_beg.key = HAMMER_MIN_KEY;
 2645 
 2646         cursor.key_end = cursor.key_beg;
 2647         cursor.key_end.rec_type = 0xFFFF;
 2648         cursor.key_end.key = HAMMER_MAX_KEY;
 2649 
 2650         cursor.asof = ip->obj_asof;
 2651         cursor.flags |= HAMMER_CURSOR_END_INCLUSIVE | HAMMER_CURSOR_ASOF;
 2652 
 2653         error = hammer_ip_first(&cursor);
 2654         if (error == ENOENT)
 2655                 error = 0;
 2656         else if (error == 0)
 2657                 error = ENOTEMPTY;
 2658         hammer_done_cursor(&cursor);
 2659         return(error);
 2660 }
 2661 
 2662 /*
 2663  * Localize the data payload.  Directory entries may need their
 2664  * localization adjusted.
 2665  */
 2666 static
 2667 int
 2668 hammer_cursor_localize_data(hammer_data_ondisk_t data,
 2669                             hammer_btree_leaf_elm_t leaf)
 2670 {
 2671         u_int32_t localization;
 2672 
 2673         if (leaf->base.rec_type == HAMMER_RECTYPE_DIRENTRY) {
 2674                 localization = leaf->base.localization &
 2675                                HAMMER_LOCALIZE_PSEUDOFS_MASK;
 2676                 if (data->entry.localization != localization) {
 2677                         data->entry.localization = localization;
 2678                         hammer_crc_set_leaf(data, leaf);
 2679                 }
 2680         }
 2681         return(0);
 2682 }

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