From: Tom Lane Date: Tue, 22 Jul 2014 15:45:50 +0000 (-0400) Subject: Check block number against the correct fork in get_raw_page(). X-Git-Tag: REL9_4_BETA3~147 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1ea941450bca70ec9e30c2936e99835f9649f865;p=postgresql 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. --- diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c index cc66fc8b04..fe60fadaf3 100644 --- a/contrib/pageinspect/rawpage.c +++ b/contrib/pageinspect/rawpage.c @@ -131,9 +131,11 @@ 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 c070278944..d05d237443 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -2032,8 +2032,8 @@ 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)