Replace RelationOpenSmgr() with RelationGetSmgr().
authorTom Lane <[email protected]>
Thu, 17 Nov 2022 21:54:30 +0000 (16:54 -0500)
committerTom Lane <[email protected]>
Thu, 17 Nov 2022 21:54:30 +0000 (16:54 -0500)
This is a back-patch of the v15-era commit f10f0ae42 into older
supported branches.  The idea is to design out bugs in which an
ill-timed relcache flush clears rel->rd_smgr partway through
some code sequence that wasn't expecting that.  We had another
report today of a corner case that reliably crashes v14 under
debug_discard_caches (nee CLOBBER_CACHE_ALWAYS), and therefore
would crash once in a blue moon in the field.  We're unlikely
to get rid of all such code paths unless we adopt the more
rigorous coding rules instituted by f10f0ae42.  Therefore,
even though this is a bit invasive, it's time to back-patch.
Some comfort can be taken in the fact that f10f0ae42 has been
in v15 for 16 months without problems.

I left the RelationOpenSmgr macro present in the back branches,
even though no core code should use it anymore, in order to not break
third-party extensions in minor releases.  Such extensions might opt
to start using RelationGetSmgr instead, to reduce their code
differential between v15 and earlier branches.  This carries a hazard
of failing to compile against headers from existing minor releases.
However, once compiled the extension should work fine even with such
releases, because RelationGetSmgr is a "static inline" function so
it creates no link-time dependency.  So depending on distribution
practices, that might be an OK tradeoff.

Per report from Spyridon Dimitrios Agathos.  Original patch
by Amul Sul.

Discussion: https://postgr.es/m/CAFM5RaqdgyusQvmWkyPYaWMwoK5gigdtW-7HcgHgOeAw7mqJ_Q@mail.gmail.com
Discussion: https://postgr.es/m/CANiYTQsU7yMFpQYnv=BrcRVqK_3U3mtAzAsJCaqtzsDHfsUbdQ@mail.gmail.com

21 files changed:
contrib/amcheck/verify_nbtree.c
contrib/bloom/blinsert.c
contrib/pg_prewarm/autoprewarm.c
contrib/pg_prewarm/pg_prewarm.c
contrib/pg_visibility/pg_visibility.c
src/backend/access/gist/gistbuild.c
src/backend/access/hash/hashpage.c
src/backend/access/heap/heapam_handler.c
src/backend/access/heap/rewriteheap.c
src/backend/access/heap/visibilitymap.c
src/backend/access/nbtree/nbtree.c
src/backend/access/nbtree/nbtsort.c
src/backend/access/spgist/spginsert.c
src/backend/access/table/tableam.c
src/backend/catalog/heap.c
src/backend/catalog/index.c
src/backend/catalog/storage.c
src/backend/commands/tablecmds.c
src/backend/storage/buffer/bufmgr.c
src/backend/storage/freespace/freespace.c
src/include/utils/rel.h

index e857dc3addc1f869422053b5b6dbefcd4583a49e..63d1f0df4dc71f6cc011cdec2d381583eb7616c7 100644 (file)
@@ -319,8 +319,7 @@ bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed,
        bool        heapkeyspace,
                    allequalimage;
 
-       RelationOpenSmgr(indrel);
-       if (!smgrexists(indrel->rd_smgr, MAIN_FORKNUM))
+       if (!smgrexists(RelationGetSmgr(indrel), MAIN_FORKNUM))
            ereport(ERROR,
                    (errcode(ERRCODE_INDEX_CORRUPTED),
                     errmsg("index \"%s\" lacks a main relation fork",
index 6d3fd5c432cd621ef380a2443a25b0ccbcd22261..00f808688f40d58f4bc98947779b18c5eef0bddf 100644 (file)
@@ -178,9 +178,9 @@ blbuildempty(Relation index)
     * this even when wal_level=minimal.
     */
    PageSetChecksumInplace(metapage, BLOOM_METAPAGE_BLKNO);
-   smgrwrite(index->rd_smgr, INIT_FORKNUM, BLOOM_METAPAGE_BLKNO,
+   smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, BLOOM_METAPAGE_BLKNO,
              (char *) metapage, true);
-   log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
+   log_newpage(&(RelationGetSmgr(index))->smgr_rnode.node, INIT_FORKNUM,
                BLOOM_METAPAGE_BLKNO, metapage, true);
 
    /*
@@ -188,7 +188,7 @@ blbuildempty(Relation index)
     * write did not go through shared_buffers and therefore a concurrent
     * checkpoint may have moved the redo pointer past our xlog record.
     */
-   smgrimmedsync(index->rd_smgr, INIT_FORKNUM);
+   smgrimmedsync(RelationGetSmgr(index), INIT_FORKNUM);
 }
 
 /*
index 1701da9dff4dee2e78ef95cee9a33b57aebd7878..31be24fc9c365f26b19b3f2873d8d4bad6cb68f6 100644 (file)
@@ -518,15 +518,13 @@ autoprewarm_database_main(Datum main_arg)
            old_blk->filenode != blk->filenode ||
            old_blk->forknum != blk->forknum)
        {
-           RelationOpenSmgr(rel);
-
            /*
             * smgrexists is not safe for illegal forknum, hence check whether
             * the passed forknum is valid before using it in smgrexists.
             */
            if (blk->forknum > InvalidForkNumber &&
                blk->forknum <= MAX_FORKNUM &&
-               smgrexists(rel->rd_smgr, blk->forknum))
+               smgrexists(RelationGetSmgr(rel), blk->forknum))
                nblocks = RelationGetNumberOfBlocksInFork(rel, blk->forknum);
            else
                nblocks = 0;
index 33e2d28b2767ed2c5ea200d641eba1eebb38851b..0d1d2b24bdb6f8a1f6719220db5820792b5a2bf3 100644 (file)
@@ -109,8 +109,7 @@ pg_prewarm(PG_FUNCTION_ARGS)
        aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind), get_rel_name(relOid));
 
    /* Check that the fork exists. */
-   RelationOpenSmgr(rel);
-   if (!smgrexists(rel->rd_smgr, forkNumber))
+   if (!smgrexists(RelationGetSmgr(rel), forkNumber))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("fork \"%s\" does not exist for this relation",
@@ -178,7 +177,7 @@ pg_prewarm(PG_FUNCTION_ARGS)
        for (block = first_block; block <= last_block; ++block)
        {
            CHECK_FOR_INTERRUPTS();
-           smgrread(rel->rd_smgr, forkNumber, block, blockbuffer.data);
+           smgrread(RelationGetSmgr(rel), forkNumber, block, blockbuffer.data);
            ++blocks_done;
        }
    }
index 68d580ed1e02c65c97d41c0f82bf442dc6a6485a..bb6dc3803701a3ddb7ee8114dcfb887cfa263e30 100644 (file)
@@ -391,14 +391,14 @@ pg_truncate_visibility_map(PG_FUNCTION_ARGS)
    /* Only some relkinds have a visibility map */
    check_relation_relkind(rel);
 
-   RelationOpenSmgr(rel);
-   rel->rd_smgr->smgr_vm_nblocks = InvalidBlockNumber;
+   /* Forcibly reset cached file size */
+   RelationGetSmgr(rel)->smgr_vm_nblocks = InvalidBlockNumber;
 
    block = visibilitymap_prepare_truncate(rel, 0);
    if (BlockNumberIsValid(block))
    {
        fork = VISIBILITYMAP_FORKNUM;
-       smgrtruncate(rel->rd_smgr, &fork, 1, &block);
+       smgrtruncate(RelationGetSmgr(rel), &fork, 1, &block);
    }
 
    if (RelationNeedsWAL(rel))
index 671b5e9186ff0972e3f0af0284f0c87a4d1c7050..25b5d81cd67cbb2e6cacacf7339ed9326ef0b923 100644 (file)
@@ -495,7 +495,7 @@ gistBuildCallback(Relation index,
     */
    if ((buildstate->bufferingMode == GIST_BUFFERING_AUTO &&
         buildstate->indtuples % BUFFERING_MODE_SWITCH_CHECK_STEP == 0 &&
-        effective_cache_size < smgrnblocks(index->rd_smgr, MAIN_FORKNUM)) ||
+        effective_cache_size < smgrnblocks(RelationGetSmgr(index), MAIN_FORKNUM)) ||
        (buildstate->bufferingMode == GIST_BUFFERING_STATS &&
         buildstate->indtuples >= BUFFERING_MODE_TUPLE_SIZE_STATS_TARGET))
    {
index 1e6cf49fb181444175bdac812909be5f300c4e9f..6ac53579cdb9466ddb5a8dc4cd58ad5366f4864c 100644 (file)
@@ -1028,9 +1028,9 @@ _hash_alloc_buckets(Relation rel, BlockNumber firstblock, uint32 nblocks)
                    zerobuf.data,
                    true);
 
-   RelationOpenSmgr(rel);
    PageSetChecksumInplace(page, lastblock);
-   smgrextend(rel->rd_smgr, MAIN_FORKNUM, lastblock, zerobuf.data, false);
+   smgrextend(RelationGetSmgr(rel), MAIN_FORKNUM, lastblock, zerobuf.data,
+              false);
 
    return true;
 }
index b772f713233e446f69f7c3454a1de9e452911d8d..8b0e5eb2d79dd3ab4d91d7726ac7c506b0a1cc84 100644 (file)
@@ -626,7 +626,6 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
    SMgrRelation dstrel;
 
    dstrel = smgropen(*newrnode, rel->rd_backend);
-   RelationOpenSmgr(rel);
 
    /*
     * Since we copy the file directly without looking at the shared buffers,
@@ -646,14 +645,14 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
    RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
 
    /* copy main fork */
-   RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
+   RelationCopyStorage(RelationGetSmgr(rel), dstrel, MAIN_FORKNUM,
                        rel->rd_rel->relpersistence);
 
    /* copy those extra forks that exist */
    for (ForkNumber forkNum = MAIN_FORKNUM + 1;
         forkNum <= MAX_FORKNUM; forkNum++)
    {
-       if (smgrexists(rel->rd_smgr, forkNum))
+       if (smgrexists(RelationGetSmgr(rel), forkNum))
        {
            smgrcreate(dstrel, forkNum, false);
 
@@ -665,7 +664,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
                (rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED &&
                 forkNum == INIT_FORKNUM))
                log_smgrcreate(newrnode, forkNum);
-           RelationCopyStorage(rel->rd_smgr, dstrel, forkNum,
+           RelationCopyStorage(RelationGetSmgr(rel), dstrel, forkNum,
                                rel->rd_rel->relpersistence);
        }
    }
index 39748bbd85b632c0d726267d94682010907932ba..6aae7df2e736f0052d7eefce1b4444b47197c8c1 100644 (file)
@@ -327,9 +327,8 @@ end_heap_rewrite(RewriteState state)
 
        PageSetChecksumInplace(state->rs_buffer, state->rs_blockno);
 
-       RelationOpenSmgr(state->rs_new_rel);
-       smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM, state->rs_blockno,
-                  (char *) state->rs_buffer, true);
+       smgrextend(RelationGetSmgr(state->rs_new_rel), MAIN_FORKNUM,
+                  state->rs_blockno, (char *) state->rs_buffer, true);
    }
 
    /*
@@ -340,11 +339,7 @@ end_heap_rewrite(RewriteState state)
     * wrote before the checkpoint.
     */
    if (RelationNeedsWAL(state->rs_new_rel))
-   {
-       /* for an empty table, this could be first smgr access */
-       RelationOpenSmgr(state->rs_new_rel);
-       smgrimmedsync(state->rs_new_rel->rd_smgr, MAIN_FORKNUM);
-   }
+       smgrimmedsync(RelationGetSmgr(state->rs_new_rel), MAIN_FORKNUM);
 
    logical_end_heap_rewrite(state);
 
@@ -692,11 +687,9 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
             * need for smgr to schedule an fsync for this write; we'll do it
             * ourselves in end_heap_rewrite.
             */
-           RelationOpenSmgr(state->rs_new_rel);
-
            PageSetChecksumInplace(page, state->rs_blockno);
 
-           smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM,
+           smgrextend(RelationGetSmgr(state->rs_new_rel), MAIN_FORKNUM,
                       state->rs_blockno, (char *) page, true);
 
            state->rs_blockno++;
index 0a51678c40df103c1c36e83a7cfba061ffa9c24c..6a14039ea7bb31011a50deddb88399d8e733d715 100644 (file)
@@ -455,13 +455,11 @@ visibilitymap_prepare_truncate(Relation rel, BlockNumber nheapblocks)
    elog(DEBUG1, "vm_truncate %s %d", RelationGetRelationName(rel), nheapblocks);
 #endif
 
-   RelationOpenSmgr(rel);
-
    /*
     * If no visibility map has been created yet for this relation, there's
     * nothing to truncate.
     */
-   if (!smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
+   if (!smgrexists(RelationGetSmgr(rel), VISIBILITYMAP_FORKNUM))
        return InvalidBlockNumber;
 
    /*
@@ -528,7 +526,7 @@ visibilitymap_prepare_truncate(Relation rel, BlockNumber nheapblocks)
    else
        newnblocks = truncBlock;
 
-   if (smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM) <= newnblocks)
+   if (smgrnblocks(RelationGetSmgr(rel), VISIBILITYMAP_FORKNUM) <= newnblocks)
    {
        /* nothing to do, the file was already smaller than requested size */
        return InvalidBlockNumber;
@@ -547,31 +545,30 @@ static Buffer
 vm_readbuf(Relation rel, BlockNumber blkno, bool extend)
 {
    Buffer      buf;
+   SMgrRelation reln;
 
    /*
-    * We might not have opened the relation at the smgr level yet, or we
-    * might have been forced to close it by a sinval message.  The code below
-    * won't necessarily notice relation extension immediately when extend =
-    * false, so we rely on sinval messages to ensure that our ideas about the
-    * size of the map aren't too far out of date.
+    * Caution: re-using this smgr pointer could fail if the relcache entry
+    * gets closed.  It's safe as long as we only do smgr-level operations
+    * between here and the last use of the pointer.
     */
-   RelationOpenSmgr(rel);
+   reln = RelationGetSmgr(rel);
 
    /*
     * If we haven't cached the size of the visibility map fork yet, check it
     * first.
     */
-   if (rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber)
+   if (reln->smgr_vm_nblocks == InvalidBlockNumber)
    {
-       if (smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
-           rel->rd_smgr->smgr_vm_nblocks = smgrnblocks(rel->rd_smgr,
-                                                       VISIBILITYMAP_FORKNUM);
+       if (smgrexists(reln, VISIBILITYMAP_FORKNUM))
+           reln->smgr_vm_nblocks = smgrnblocks(reln,
+                                               VISIBILITYMAP_FORKNUM);
        else
-           rel->rd_smgr->smgr_vm_nblocks = 0;
+           reln->smgr_vm_nblocks = 0;
    }
 
    /* Handle requests beyond EOF */
-   if (blkno >= rel->rd_smgr->smgr_vm_nblocks)
+   if (blkno >= reln->smgr_vm_nblocks)
    {
        if (extend)
            vm_extend(rel, blkno + 1);
@@ -619,6 +616,7 @@ vm_extend(Relation rel, BlockNumber vm_nblocks)
 {
    BlockNumber vm_nblocks_now;
    PGAlignedBlock pg;
+   SMgrRelation reln;
 
    PageInit((Page) pg.data, BLCKSZ, 0);
 
@@ -634,26 +632,30 @@ vm_extend(Relation rel, BlockNumber vm_nblocks)
     */
    LockRelationForExtension(rel, ExclusiveLock);
 
-   /* Might have to re-open if a cache flush happened */
-   RelationOpenSmgr(rel);
+   /*
+    * Caution: re-using this smgr pointer could fail if the relcache entry
+    * gets closed.  It's safe as long as we only do smgr-level operations
+    * between here and the last use of the pointer.
+    */
+   reln = RelationGetSmgr(rel);
 
    /*
     * Create the file first if it doesn't exist.  If smgr_vm_nblocks is
     * positive then it must exist, no need for an smgrexists call.
     */
-   if ((rel->rd_smgr->smgr_vm_nblocks == 0 ||
-        rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber) &&
-       !smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
-       smgrcreate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, false);
+   if ((reln->smgr_vm_nblocks == 0 ||
+        reln->smgr_vm_nblocks == InvalidBlockNumber) &&
+       !smgrexists(reln, VISIBILITYMAP_FORKNUM))
+       smgrcreate(reln, VISIBILITYMAP_FORKNUM, false);
 
-   vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
+   vm_nblocks_now = smgrnblocks(reln, VISIBILITYMAP_FORKNUM);
 
    /* Now extend the file */
    while (vm_nblocks_now < vm_nblocks)
    {
        PageSetChecksumInplace((Page) pg.data, vm_nblocks_now);
 
-       smgrextend(rel->rd_smgr, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
+       smgrextend(reln, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
                   pg.data, false);
        vm_nblocks_now++;
    }
@@ -665,10 +667,10 @@ vm_extend(Relation rel, BlockNumber vm_nblocks)
     * to keep checking for creation or extension of the file, which happens
     * infrequently.
     */
-   CacheInvalidateSmgr(rel->rd_smgr->smgr_rnode);
+   CacheInvalidateSmgr(reln->smgr_rnode);
 
    /* Update local cache with the up-to-date size */
-   rel->rd_smgr->smgr_vm_nblocks = vm_nblocks_now;
+   reln->smgr_vm_nblocks = vm_nblocks_now;
 
    UnlockRelationForExtension(rel, ExclusiveLock);
 }
index c37bbe53f986d1a81430b4e46995f1ad5a9d33c6..e8c87e1edf2b435064377cfcf0211c31c48d9919 100644 (file)
@@ -175,9 +175,9 @@ btbuildempty(Relation index)
     * this even when wal_level=minimal.
     */
    PageSetChecksumInplace(metapage, BTREE_METAPAGE);
-   smgrwrite(index->rd_smgr, INIT_FORKNUM, BTREE_METAPAGE,
+   smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, BTREE_METAPAGE,
              (char *) metapage, true);
-   log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
+   log_newpage(&RelationGetSmgr(index)->smgr_rnode.node, INIT_FORKNUM,
                BTREE_METAPAGE, metapage, true);
 
    /*
@@ -185,7 +185,7 @@ btbuildempty(Relation index)
     * write did not go through shared_buffers and therefore a concurrent
     * checkpoint may have moved the redo pointer past our xlog record.
     */
-   smgrimmedsync(index->rd_smgr, INIT_FORKNUM);
+   smgrimmedsync(RelationGetSmgr(index), INIT_FORKNUM);
 }
 
 /*
index bde61b7c5f0f953a96b8c9cf14b6f0c7fa7e25c3..315889a791eff70cd0c61a913032a45a14f65835 100644 (file)
@@ -638,9 +638,6 @@ _bt_blnewpage(uint32 level)
 static void
 _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 {
-   /* Ensure rd_smgr is open (could have been closed by relcache flush!) */
-   RelationOpenSmgr(wstate->index);
-
    /* XLOG stuff */
    if (wstate->btws_use_wal)
    {
@@ -660,7 +657,7 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
        if (!wstate->btws_zeropage)
            wstate->btws_zeropage = (Page) palloc0(BLCKSZ);
        /* don't set checksum for all-zero page */
-       smgrextend(wstate->index->rd_smgr, MAIN_FORKNUM,
+       smgrextend(RelationGetSmgr(wstate->index), MAIN_FORKNUM,
                   wstate->btws_pages_written++,
                   (char *) wstate->btws_zeropage,
                   true);
@@ -675,14 +672,14 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
    if (blkno == wstate->btws_pages_written)
    {
        /* extending the file... */
-       smgrextend(wstate->index->rd_smgr, MAIN_FORKNUM, blkno,
+       smgrextend(RelationGetSmgr(wstate->index), MAIN_FORKNUM, blkno,
                   (char *) page, true);
        wstate->btws_pages_written++;
    }
    else
    {
        /* overwriting a block we zero-filled before */
-       smgrwrite(wstate->index->rd_smgr, MAIN_FORKNUM, blkno,
+       smgrwrite(RelationGetSmgr(wstate->index), MAIN_FORKNUM, blkno,
                  (char *) page, true);
    }
 
@@ -1428,10 +1425,7 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
     * still not be on disk when the crash occurs.
     */
    if (wstate->btws_use_wal)
-   {
-       RelationOpenSmgr(wstate->index);
-       smgrimmedsync(wstate->index->rd_smgr, MAIN_FORKNUM);
-   }
+       smgrimmedsync(RelationGetSmgr(wstate->index), MAIN_FORKNUM);
 }
 
 /*
index e4508a2b923a254c71e0d043b48056d3e53a9a10..5a579354b780fada99225e240dc13e1e14f8cf71 100644 (file)
@@ -169,27 +169,27 @@ spgbuildempty(Relation index)
     * replayed.
     */
    PageSetChecksumInplace(page, SPGIST_METAPAGE_BLKNO);
-   smgrwrite(index->rd_smgr, INIT_FORKNUM, SPGIST_METAPAGE_BLKNO,
+   smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, SPGIST_METAPAGE_BLKNO,
              (char *) page, true);
-   log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
+   log_newpage(&(RelationGetSmgr(index))->smgr_rnode.node, INIT_FORKNUM,
                SPGIST_METAPAGE_BLKNO, page, true);
 
    /* Likewise for the root page. */
    SpGistInitPage(page, SPGIST_LEAF);
 
    PageSetChecksumInplace(page, SPGIST_ROOT_BLKNO);
-   smgrwrite(index->rd_smgr, INIT_FORKNUM, SPGIST_ROOT_BLKNO,
+   smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, SPGIST_ROOT_BLKNO,
              (char *) page, true);
-   log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
+   log_newpage(&(RelationGetSmgr(index))->smgr_rnode.node, INIT_FORKNUM,
                SPGIST_ROOT_BLKNO, page, true);
 
    /* Likewise for the null-tuples root page. */
    SpGistInitPage(page, SPGIST_LEAF | SPGIST_NULLS);
 
    PageSetChecksumInplace(page, SPGIST_NULL_BLKNO);
-   smgrwrite(index->rd_smgr, INIT_FORKNUM, SPGIST_NULL_BLKNO,
+   smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, SPGIST_NULL_BLKNO,
              (char *) page, true);
-   log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
+   log_newpage(&(RelationGetSmgr(index))->smgr_rnode.node, INIT_FORKNUM,
                SPGIST_NULL_BLKNO, page, true);
 
    /*
@@ -197,7 +197,7 @@ spgbuildempty(Relation index)
     * writes did not go through shared buffers and therefore a concurrent
     * checkpoint may have moved the redo pointer past our xlog record.
     */
-   smgrimmedsync(index->rd_smgr, INIT_FORKNUM);
+   smgrimmedsync(RelationGetSmgr(index), INIT_FORKNUM);
 }
 
 /*
index 4b2bb29559a72aac9436e112060b3b1d5b1d7069..4e43813530f4fed3e904c0f4e35a38c50b417618 100644 (file)
@@ -513,17 +513,14 @@ table_block_relation_size(Relation rel, ForkNumber forkNumber)
 {
    uint64      nblocks = 0;
 
-   /* Open it at the smgr level if not already done */
-   RelationOpenSmgr(rel);
-
    /* InvalidForkNumber indicates returning the size for all forks */
    if (forkNumber == InvalidForkNumber)
    {
        for (int i = 0; i < MAX_FORKNUM; i++)
-           nblocks += smgrnblocks(rel->rd_smgr, i);
+           nblocks += smgrnblocks(RelationGetSmgr(rel), i);
    }
    else
-       nblocks = smgrnblocks(rel->rd_smgr, forkNumber);
+       nblocks = smgrnblocks(RelationGetSmgr(rel), forkNumber);
 
    return nblocks * BLCKSZ;
 }
index a42070fd9250b3e2d382d2e8e37ea255314cf2c1..fa24be1a32005e8a3086ae379a6dba056c58ad17 100644 (file)
@@ -413,8 +413,6 @@ heap_create(const char *relname,
     */
    if (create_storage)
    {
-       RelationOpenSmgr(rel);
-
        switch (rel->rd_rel->relkind)
        {
            case RELKIND_VIEW:
index 602b51a6a790fba0ae8af85fb168444363bda6df..64a45f4ed4aeb7319bca62c27b4c98ea2b07dc55 100644 (file)
@@ -3010,10 +3010,9 @@ index_build(Relation heapRelation,
     * relfilenode won't change, and nothing needs to be done here.
     */
    if (indexRelation->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED &&
-       !smgrexists(indexRelation->rd_smgr, INIT_FORKNUM))
+       !smgrexists(RelationGetSmgr(indexRelation), INIT_FORKNUM))
    {
-       RelationOpenSmgr(indexRelation);
-       smgrcreate(indexRelation->rd_smgr, INIT_FORKNUM, false);
+       smgrcreate(RelationGetSmgr(indexRelation), INIT_FORKNUM, false);
        indexRelation->rd_indam->ambuildempty(indexRelation);
    }
 
index d7c74105a4e93752fb5a1cac1e17090bf88b9621..b823f5080842ad7a6b295c6d1d823fd52ddf5317 100644 (file)
@@ -282,16 +282,16 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
    ForkNumber  forks[MAX_FORKNUM];
    BlockNumber blocks[MAX_FORKNUM];
    int         nforks = 0;
-
-   /* Open it at the smgr level if not already done */
-   RelationOpenSmgr(rel);
+   SMgrRelation reln;
 
    /*
-    * Make sure smgr_targblock etc aren't pointing somewhere past new end
+    * Make sure smgr_targblock etc aren't pointing somewhere past new end.
+    * (Note: don't rely on this reln pointer below here.)
     */
-   rel->rd_smgr->smgr_targblock = InvalidBlockNumber;
-   rel->rd_smgr->smgr_fsm_nblocks = InvalidBlockNumber;
-   rel->rd_smgr->smgr_vm_nblocks = InvalidBlockNumber;
+   reln = RelationGetSmgr(rel);
+   reln->smgr_targblock = InvalidBlockNumber;
+   reln->smgr_fsm_nblocks = InvalidBlockNumber;
+   reln->smgr_vm_nblocks = InvalidBlockNumber;
 
    /* Prepare for truncation of MAIN fork of the relation */
    forks[nforks] = MAIN_FORKNUM;
@@ -299,7 +299,7 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
    nforks++;
 
    /* Prepare for truncation of the FSM if it exists */
-   fsm = smgrexists(rel->rd_smgr, FSM_FORKNUM);
+   fsm = smgrexists(RelationGetSmgr(rel), FSM_FORKNUM);
    if (fsm)
    {
        blocks[nforks] = FreeSpaceMapPrepareTruncateRel(rel, nblocks);
@@ -312,7 +312,7 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
    }
 
    /* Prepare for truncation of the visibility map too if it exists */
-   vm = smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
+   vm = smgrexists(RelationGetSmgr(rel), VISIBILITYMAP_FORKNUM);
    if (vm)
    {
        blocks[nforks] = visibilitymap_prepare_truncate(rel, nblocks);
@@ -384,7 +384,7 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
     * longer exist after truncation is complete, and then truncate the
     * corresponding files on disk.
     */
-   smgrtruncate(rel->rd_smgr, forks, nforks, blocks);
+   smgrtruncate(RelationGetSmgr(rel), forks, nforks, blocks);
 
    /* We've done all the critical work, so checkpoints are OK now. */
    MyProc->delayChkptEnd = false;
@@ -416,9 +416,9 @@ RelationPreTruncate(Relation rel)
 
    if (!pendingSyncHash)
        return;
-   RelationOpenSmgr(rel);
 
-   pending = hash_search(pendingSyncHash, &(rel->rd_smgr->smgr_rnode.node),
+   pending = hash_search(pendingSyncHash,
+                         &(RelationGetSmgr(rel)->smgr_rnode.node),
                          HASH_FIND, NULL);
    if (pending)
        pending->is_truncated = true;
@@ -430,6 +430,12 @@ RelationPreTruncate(Relation rel)
  * Note that this requires that there is no dirty data in shared buffers. If
  * it's possible that there are, callers need to flush those using
  * e.g. FlushRelationBuffers(rel).
+ *
+ * Also note that this is frequently called via locutions such as
+ *     RelationCopyStorage(RelationGetSmgr(rel), ...);
+ * That's safe only because we perform only smgr and WAL operations here.
+ * If we invoked anything else, a relcache flush could cause our SMgrRelation
+ * argument to become a dangling pointer.
  */
 void
 RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
@@ -472,13 +478,23 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
 
        if (!PageIsVerifiedExtended(page, blkno,
                                    PIV_LOG_WARNING | PIV_REPORT_STAT))
+       {
+           /*
+            * For paranoia's sake, capture the file path before invoking the
+            * ereport machinery.  This guards against the possibility of a
+            * relcache flush caused by, e.g., an errcontext callback.
+            * (errcontext callbacks shouldn't be risking any such thing, but
+            * people have been known to forget that rule.)
+            */
+           char       *relpath = relpathbackend(src->smgr_rnode.node,
+                                                src->smgr_rnode.backend,
+                                                forkNum);
+
            ereport(ERROR,
                    (errcode(ERRCODE_DATA_CORRUPTED),
                     errmsg("invalid page in block %u of relation %s",
-                           blkno,
-                           relpathbackend(src->smgr_rnode.node,
-                                          src->smgr_rnode.backend,
-                                          forkNum))));
+                           blkno, relpath)));
+       }
 
        /*
         * WAL-log the copied page. Unfortunately we don't know what kind of a
index 425630228f4c08af189361ce565b1af92a2602bd..bcc7d3c29c437831bfc97add5c7d610e430e072a 100644 (file)
@@ -13798,7 +13798,6 @@ index_copy_data(Relation rel, RelFileNode newrnode)
    SMgrRelation dstrel;
 
    dstrel = smgropen(newrnode, rel->rd_backend);
-   RelationOpenSmgr(rel);
 
    /*
     * Since we copy the file directly without looking at the shared buffers,
@@ -13818,14 +13817,14 @@ index_copy_data(Relation rel, RelFileNode newrnode)
    RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
 
    /* copy main fork */
-   RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
+   RelationCopyStorage(RelationGetSmgr(rel), dstrel, MAIN_FORKNUM,
                        rel->rd_rel->relpersistence);
 
    /* copy those extra forks that exist */
    for (ForkNumber forkNum = MAIN_FORKNUM + 1;
         forkNum <= MAX_FORKNUM; forkNum++)
    {
-       if (smgrexists(rel->rd_smgr, forkNum))
+       if (smgrexists(RelationGetSmgr(rel), forkNum))
        {
            smgrcreate(dstrel, forkNum, false);
 
@@ -13837,7 +13836,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
                (rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED &&
                 forkNum == INIT_FORKNUM))
                log_smgrcreate(&newrnode, forkNum);
-           RelationCopyStorage(rel->rd_smgr, dstrel, forkNum,
+           RelationCopyStorage(RelationGetSmgr(rel), dstrel, forkNum,
                                rel->rd_rel->relpersistence);
        }
    }
index b32184591f69c78e970cea877a9981c0fe4e0a27..69a14016547b820a576672edeae6a0c5d9f1c11f 100644 (file)
@@ -576,9 +576,6 @@ PrefetchBuffer(Relation reln, ForkNumber forkNum, BlockNumber blockNum)
    Assert(RelationIsValid(reln));
    Assert(BlockNumberIsValid(blockNum));
 
-   /* Open it at the smgr level if not already done */
-   RelationOpenSmgr(reln);
-
    if (RelationUsesLocalBuffers(reln))
    {
        /* see comments in ReadBufferExtended */
@@ -588,12 +585,12 @@ PrefetchBuffer(Relation reln, ForkNumber forkNum, BlockNumber blockNum)
                     errmsg("cannot access temporary tables of other sessions")));
 
        /* pass it off to localbuf.c */
-       return PrefetchLocalBuffer(reln->rd_smgr, forkNum, blockNum);
+       return PrefetchLocalBuffer(RelationGetSmgr(reln), forkNum, blockNum);
    }
    else
    {
        /* pass it to the shared buffer version */
-       return PrefetchSharedBuffer(reln->rd_smgr, forkNum, blockNum);
+       return PrefetchSharedBuffer(RelationGetSmgr(reln), forkNum, blockNum);
    }
 }
 
@@ -656,9 +653,6 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
    bool        hit;
    Buffer      buf;
 
-   /* Open it at the smgr level if not already done */
-   RelationOpenSmgr(reln);
-
    /*
     * Reject attempts to read non-local temporary relations; we would be
     * likely to get wrong data since we have no visibility into the owning
@@ -674,7 +668,7 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
     * miss.
     */
    pgstat_count_buffer_read(reln);
-   buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
+   buf = ReadBuffer_common(RelationGetSmgr(reln), reln->rd_rel->relpersistence,
                            forkNum, blockNum, mode, strategy, &hit);
    if (hit)
        pgstat_count_buffer_hit(reln);
@@ -2835,10 +2829,7 @@ RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
        case RELKIND_SEQUENCE:
        case RELKIND_INDEX:
        case RELKIND_PARTITIONED_INDEX:
-           /* Open it at the smgr level if not already done */
-           RelationOpenSmgr(relation);
-
-           return smgrnblocks(relation->rd_smgr, forkNum);
+           return smgrnblocks(RelationGetSmgr(relation), forkNum);
 
        case RELKIND_RELATION:
        case RELKIND_TOASTVALUE:
@@ -3237,9 +3228,6 @@ FlushRelationBuffers(Relation rel)
    int         i;
    BufferDesc *bufHdr;
 
-   /* Open rel at the smgr level if not already done */
-   RelationOpenSmgr(rel);
-
    if (RelationUsesLocalBuffers(rel))
    {
        for (i = 0; i < NLocBuffer; i++)
@@ -3264,7 +3252,7 @@ FlushRelationBuffers(Relation rel)
 
                PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
 
-               smgrwrite(rel->rd_smgr,
+               smgrwrite(RelationGetSmgr(rel),
                          bufHdr->tag.forkNum,
                          bufHdr->tag.blockNum,
                          localpage,
@@ -3305,7 +3293,7 @@ FlushRelationBuffers(Relation rel)
        {
            PinBuffer_Locked(bufHdr);
            LWLockAcquire(BufferDescriptorGetContentLock(bufHdr), LW_SHARED);
-           FlushBuffer(bufHdr, rel->rd_smgr);
+           FlushBuffer(bufHdr, RelationGetSmgr(rel));
            LWLockRelease(BufferDescriptorGetContentLock(bufHdr));
            UnpinBuffer(bufHdr, true);
        }
index 95a21f6cc383eac012f998b10b595817bcd77f66..72cce7a84f25299233739301c29e0e3e7eb79f02 100644 (file)
@@ -265,13 +265,11 @@ FreeSpaceMapPrepareTruncateRel(Relation rel, BlockNumber nblocks)
    uint16      first_removed_slot;
    Buffer      buf;
 
-   RelationOpenSmgr(rel);
-
    /*
     * If no FSM has been created yet for this relation, there's nothing to
     * truncate.
     */
-   if (!smgrexists(rel->rd_smgr, FSM_FORKNUM))
+   if (!smgrexists(RelationGetSmgr(rel), FSM_FORKNUM))
        return InvalidBlockNumber;
 
    /* Get the location in the FSM of the first removed heap block */
@@ -317,7 +315,7 @@ FreeSpaceMapPrepareTruncateRel(Relation rel, BlockNumber nblocks)
    else
    {
        new_nfsmblocks = fsm_logical_to_physical(first_removed_address);
-       if (smgrnblocks(rel->rd_smgr, FSM_FORKNUM) <= new_nfsmblocks)
+       if (smgrnblocks(RelationGetSmgr(rel), FSM_FORKNUM) <= new_nfsmblocks)
            return InvalidBlockNumber;  /* nothing to do; the FSM was already
                                         * smaller */
    }
@@ -532,8 +530,14 @@ fsm_readbuf(Relation rel, FSMAddress addr, bool extend)
 {
    BlockNumber blkno = fsm_logical_to_physical(addr);
    Buffer      buf;
+   SMgrRelation reln;
 
-   RelationOpenSmgr(rel);
+   /*
+    * Caution: re-using this smgr pointer could fail if the relcache entry
+    * gets closed.  It's safe as long as we only do smgr-level operations
+    * between here and the last use of the pointer.
+    */
+   reln = RelationGetSmgr(rel);
 
    /*
     * If we haven't cached the size of the FSM yet, check it first.  Also
@@ -541,18 +545,18 @@ fsm_readbuf(Relation rel, FSMAddress addr, bool extend)
     * value might be stale.  (We send smgr inval messages on truncation, but
     * not on extension.)
     */
-   if (rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber ||
-       blkno >= rel->rd_smgr->smgr_fsm_nblocks)
+   if (reln->smgr_fsm_nblocks == InvalidBlockNumber ||
+       blkno >= reln->smgr_fsm_nblocks)
    {
-       if (smgrexists(rel->rd_smgr, FSM_FORKNUM))
-           rel->rd_smgr->smgr_fsm_nblocks = smgrnblocks(rel->rd_smgr,
-                                                        FSM_FORKNUM);
+       if (smgrexists(reln, FSM_FORKNUM))
+           reln->smgr_fsm_nblocks = smgrnblocks(reln,
+                                                FSM_FORKNUM);
        else
-           rel->rd_smgr->smgr_fsm_nblocks = 0;
+           reln->smgr_fsm_nblocks = 0;
    }
 
    /* Handle requests beyond EOF */
-   if (blkno >= rel->rd_smgr->smgr_fsm_nblocks)
+   if (blkno >= reln->smgr_fsm_nblocks)
    {
        if (extend)
            fsm_extend(rel, blkno + 1);
@@ -602,6 +606,7 @@ fsm_extend(Relation rel, BlockNumber fsm_nblocks)
 {
    BlockNumber fsm_nblocks_now;
    PGAlignedBlock pg;
+   SMgrRelation reln;
 
    PageInit((Page) pg.data, BLCKSZ, 0);
 
@@ -617,31 +622,35 @@ fsm_extend(Relation rel, BlockNumber fsm_nblocks)
     */
    LockRelationForExtension(rel, ExclusiveLock);
 
-   /* Might have to re-open if a cache flush happened */
-   RelationOpenSmgr(rel);
+   /*
+    * Caution: re-using this smgr pointer could fail if the relcache entry
+    * gets closed.  It's safe as long as we only do smgr-level operations
+    * between here and the last use of the pointer.
+    */
+   reln = RelationGetSmgr(rel);
 
    /*
     * Create the FSM file first if it doesn't exist.  If smgr_fsm_nblocks is
     * positive then it must exist, no need for an smgrexists call.
     */
-   if ((rel->rd_smgr->smgr_fsm_nblocks == 0 ||
-        rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber) &&
-       !smgrexists(rel->rd_smgr, FSM_FORKNUM))
-       smgrcreate(rel->rd_smgr, FSM_FORKNUM, false);
+   if ((reln->smgr_fsm_nblocks == 0 ||
+        reln->smgr_fsm_nblocks == InvalidBlockNumber) &&
+       !smgrexists(reln, FSM_FORKNUM))
+       smgrcreate(reln, FSM_FORKNUM, false);
 
-   fsm_nblocks_now = smgrnblocks(rel->rd_smgr, FSM_FORKNUM);
+   fsm_nblocks_now = smgrnblocks(reln, FSM_FORKNUM);
 
    while (fsm_nblocks_now < fsm_nblocks)
    {
        PageSetChecksumInplace((Page) pg.data, fsm_nblocks_now);
 
-       smgrextend(rel->rd_smgr, FSM_FORKNUM, fsm_nblocks_now,
+       smgrextend(reln, FSM_FORKNUM, fsm_nblocks_now,
                   pg.data, false);
        fsm_nblocks_now++;
    }
 
    /* Update local cache with the up-to-date size */
-   rel->rd_smgr->smgr_fsm_nblocks = fsm_nblocks_now;
+   reln->smgr_fsm_nblocks = fsm_nblocks_now;
 
    UnlockRelationForExtension(rel, ExclusiveLock);
 }
index b7c10864eb5985b7cd71e355e1954bb7961908c7..8d9f7006c3dcb374e9742f0103f6f29d64fc848e 100644 (file)
@@ -24,6 +24,7 @@
 #include "rewrite/prs2lock.h"
 #include "storage/block.h"
 #include "storage/relfilenode.h"
+#include "storage/smgr.h"
 #include "utils/relcache.h"
 #include "utils/reltrigger.h"
 
@@ -53,8 +54,7 @@ typedef LockInfoData *LockInfo;
 typedef struct RelationData
 {
    RelFileNode rd_node;        /* relation physical identifier */
-   /* use "struct" here to avoid needing to include smgr.h: */
-   struct SMgrRelationData *rd_smgr;   /* cached file handle, or NULL */
+   SMgrRelation rd_smgr;       /* cached file handle, or NULL */
    int         rd_refcnt;      /* reference count */
    BackendId   rd_backend;     /* owning backend id, if temporary relation */
    bool        rd_islocaltemp; /* rel is a temp rel of this session */
@@ -505,9 +505,33 @@ typedef struct ViewOptions
    (RELKIND_HAS_STORAGE((relation)->rd_rel->relkind) && \
     ((relation)->rd_rel->relfilenode == InvalidOid))
 
+/*
+ * RelationGetSmgr
+ *     Returns smgr file handle for a relation, opening it if needed.
+ *
+ * Very little code is authorized to touch rel->rd_smgr directly.  Instead
+ * use this function to fetch its value.
+ *
+ * Note: since a relcache flush can cause the file handle to be closed again,
+ * it's unwise to hold onto the pointer returned by this function for any
+ * long period.  Recommended practice is to just re-execute RelationGetSmgr
+ * each time you need to access the SMgrRelation.  It's quite cheap in
+ * comparison to whatever an smgr function is going to do.
+ */
+static inline SMgrRelation
+RelationGetSmgr(Relation rel)
+{
+   if (unlikely(rel->rd_smgr == NULL))
+       smgrsetowner(&(rel->rd_smgr), smgropen(rel->rd_node, rel->rd_backend));
+   return rel->rd_smgr;
+}
+
 /*
  * RelationOpenSmgr
  *     Open the relation at the smgr level, if not already done.
+ *
+ * XXX this is now deprecated, and should not be used in new code.
+ * Instead, call RelationGetSmgr in place of fetching rd_smgr directly.
  */
 #define RelationOpenSmgr(relation) \
    do { \
@@ -535,7 +559,8 @@ typedef struct ViewOptions
  *     Fetch relation's current insertion target block.
  *
  * Returns InvalidBlockNumber if there is no current target block.  Note
- * that the target block status is discarded on any smgr-level invalidation.
+ * that the target block status is discarded on any smgr-level invalidation,
+ * so there's no need to re-open the smgr handle if it's not currently open.
  */
 #define RelationGetTargetBlock(relation) \
    ( (relation)->rd_smgr != NULL ? (relation)->rd_smgr->smgr_targblock : InvalidBlockNumber )
@@ -546,8 +571,7 @@ typedef struct ViewOptions
  */
 #define RelationSetTargetBlock(relation, targblock) \
    do { \
-       RelationOpenSmgr(relation); \
-       (relation)->rd_smgr->smgr_targblock = (targblock); \
+       RelationGetSmgr(relation)->smgr_targblock = (targblock); \
    } while (0)
 
 /*