postgres.git / summary / log / commit / refs

commit    3c5232ae83cd7055a1858db4ca46031578e2fd70
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Tue Jul 22 15:46:00 2014 +0000
First released in: 9.5.0, 9.0.19, 9.1.15, 9.2.10, 9.3.6, 9.4.0

    Check block number against the correct fork in get_raw_page().
    
    get_raw_page tried to validate the supplied block number against
    RelationGetNumberOfBlocks(), which of course is only right when
    accessing the main fork.  In most cases, the main fork is longer
    than the others, so that the check was too weak (allowing a
    lower-level error to be reported, but no real harm to be done).
    However, very small tables could have an FSM larger than their heap,
    in which case the mistake prevented access to some FSM pages.
    Per report from Torsten Foertsch.
    
    In passing, make the bad-block-number error into an ereport not elog
    (since it's certainly not an internal error); and fix sloppily
    maintained comment for RelationGetNumberOfBlocksInFork.
    
    This has been wrong since we invented relation forks, so back-patch
    to all supported branches.


 contrib/pageinspect/rawpage.c       | 8 +++++---
 src/backend/storage/buffer/bufmgr.c | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index 2607576c378..1548dc2e257 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -135,9 +135,11 @@ get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot access temporary tables of other sessions")));
 
-	if (blkno >= RelationGetNumberOfBlocks(rel))
-		elog(ERROR, "block number %u is out of range for relation \"%s\"",
-			 blkno, RelationGetRelationName(rel));
+	if (blkno >= RelationGetNumberOfBlocksInFork(rel, forknum))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("block number %u is out of range for relation \"%s\"",
+						blkno, RelationGetRelationName(rel))));
 
 	/* Initialize buffer to copy to */
 	raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 58b64f6570d..aeb814e9efc 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1926,8 +1926,8 @@ FlushBuffer(volatile BufferDesc *buf, SMgrRelation reln)
 }
 
 /*
- * RelationGetNumberOfBlocks
- *		Determines the current number of pages in the relation.
+ * RelationGetNumberOfBlocksInFork
+ *		Determines the current number of pages in the specified relation fork.
  */
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)


[parent: 81af4185ad0c]