Restore smgrtruncate() prototype in back-branches.

It's possible that external code is calling smgrtruncate().  Any
external callers might like to consider the recent changes to
RelationTruncate(), but commit 38c579b0 should not have changed the
function prototype in the back-branches, per ABI stability policy.

Restore smgrtruncate()'s traditional argument list in the back-branches,
but make it a wrapper for a new function smgrtruncate2().  The three
callers in core can use smgrtruncate2() directly.  In master (18-to-be),
smgrtruncate2() is effectively renamed to smgrtruncate(), so this wart
is cleaned up.

Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKG%2BThae6x6%2BjmQiuALQBT2Ae1ChjMh1%3DkMvJ8y_SBJZrvA%40mail.gmail.com

diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index adeb9512a70eca3314137664a0019649e0aff33f..ad0f2a109a6e9cfef9697da9407d8685d2f42959 100644 (file)
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -421,7 +421,7 @@ pg_truncate_visibility_map(PG_FUNCTION_ARGS)
        }
 
        if (BlockNumberIsValid(block))
-               smgrtruncate(RelationGetSmgr(rel), &fork, 1, &old_block, &block);
+               smgrtruncate2(RelationGetSmgr(rel), &fork, 1, &old_block, &block);
 
        END_CRIT_SECTION();
        MyProc->delayChkptFlags &= ~(DELAY_CHKPT_START | DELAY_CHKPT_COMPLETE);

diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 5b22cf10990e6e2a93e55b3b28de1fa49cd07d56..11b3ea40200836779044b16a547f1a5bc2b3cffe 100644 (file)
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -418,7 +418,7 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
         * longer exist after truncation is complete, and then truncate the
         * corresponding files on disk.
         */
-       smgrtruncate(RelationGetSmgr(rel), forks, nforks, old_blocks, blocks);
+       smgrtruncate2(RelationGetSmgr(rel), forks, nforks, old_blocks, blocks);
 
        END_CRIT_SECTION();
 
@@ -1059,7 +1059,7 @@ smgr_redo(XLogReaderState *record)
                if (nforks > 0)
                {
                        START_CRIT_SECTION();
-                       smgrtruncate(reln, forks, nforks, old_blocks, blocks);
+                       smgrtruncate2(reln, forks, nforks, old_blocks, blocks);
                        END_CRIT_SECTION();
                }
 

diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index b3fb8bc3ea88089bed4c06e359dc513add086121..89d62d1dee8ba8a8b7f62510a09879a0dc51cae5 100644 (file)
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -693,6 +693,26 @@ smgrnblocks_cached(SMgrRelation reln, ForkNumber forknum)
  * smgrtruncate() -- Truncate the given forks of supplied relation to
  *                                      each specified numbers of blocks
  *
+ * Backward-compatible version of smgrtruncate2() for the benefit of external
+ * callers.  This version isn't used in PostgreSQL core code, and can't be
+ * used in a critical section.
+ */
+void
+smgrtruncate(SMgrRelation reln, ForkNumber *forknum, int nforks,
+                        BlockNumber *nblocks)
+{
+       BlockNumber old_nblocks[MAX_FORKNUM + 1];
+
+       for (int i = 0; i < nforks; ++i)
+               old_nblocks[i] = smgrnblocks(reln, forknum[i]);
+
+       return smgrtruncate2(reln, forknum, nforks, old_nblocks, nblocks);
+}
+
+/*
+ * smgrtruncate2() -- Truncate the given forks of supplied relation to
+ *                                       each specified numbers of blocks
+ *
  * The truncation is done immediately, so this can't be rolled back.
  *
  * The caller must hold AccessExclusiveLock on the relation, to ensure that
@@ -704,8 +724,8 @@ smgrnblocks_cached(SMgrRelation reln, ForkNumber forknum)
  * to this relation should be called in between.
  */
 void
-smgrtruncate(SMgrRelation reln, ForkNumber *forknum, int nforks,
-                        BlockNumber *old_nblocks, BlockNumber *nblocks)
+smgrtruncate2(SMgrRelation reln, ForkNumber *forknum, int nforks,
+                         BlockNumber *old_nblocks, BlockNumber *nblocks)
 {
        int                     i;
 

diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index 98fabe9935c973511db22c17a72b0553fea4ef89..3856d1d4f8b6c969253af94322c01728bc8ef7c6 100644 (file)
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -104,8 +104,10 @@ extern void smgrwriteback(SMgrRelation reln, ForkNumber forknum,
 extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
 extern BlockNumber smgrnblocks_cached(SMgrRelation reln, ForkNumber forknum);
 extern void smgrtruncate(SMgrRelation reln, ForkNumber *forknum, int nforks,
-                                                BlockNumber *old_nblocks,
                                                 BlockNumber *nblocks);
+extern void smgrtruncate2(SMgrRelation reln, ForkNumber *forknum, int nforks,
+                                                 BlockNumber *old_nblocks,
+                                                 BlockNumber *nblocks);
 extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
 extern void smgrregistersync(SMgrRelation reln, ForkNumber forknum);
 extern void AtEOXact_SMgr(void);