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Be more consistent about masking xl_info with ~XLR_INFO_MASK. 

Generally, WAL resource managers are only supposed to examine the
top 4 bits of a WAL record's xl_info; the rest are reserved for
the WAL mechanism itself.  A few places were not consistent about
doing this with respect to XLOG_CHECKPOINT and XLOG_SWITCH records.
There's no bug currently, since no additional bits ever get set in
these specific record types, but that might not be true forever.
Let's follow the generic coding rule here too.

Michael Paquier
This commit is contained in:
Tom Lane 2016-11-04 13:26:49 -04:00
parent 367b99bbb1
commit d5f6f13f8e
2 changed files with 10 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
src/backend/access/transam/xlog.c
View File

@ -903,8 +903,9 @@ XLogInsertRecord(XLogRecData *rdata, XLogRecPtr fpw_lsn)
pg_crc32c rdata_crc;
bool inserted;
XLogRecord *rechdr = (XLogRecord *) rdata->data;
uint8 info = rechdr->xl_info & ~XLR_INFO_MASK;
bool isLogSwitch = (rechdr->xl_rmid == RM_XLOG_ID &&
rechdr->xl_info == XLOG_SWITCH);
info == XLOG_SWITCH);
XLogRecPtr StartPos;
XLogRecPtr EndPos;
@ -6170,7 +6171,7 @@ StartupXLOG(void)
if (record != NULL)
{
memcpy(&checkPoint, XLogRecGetData(xlogreader), sizeof(CheckPoint));
wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN);
wasShutdown = ((record->xl_info & ~XLR_INFO_MASK) == XLOG_CHECKPOINT_SHUTDOWN);
ereport(DEBUG1,
(errmsg("checkpoint record is at %X/%X",
(uint32) (checkPointLoc >> 32), (uint32) checkPointLoc)));
@ -6328,7 +6329,7 @@ StartupXLOG(void)
(errmsg("could not locate a valid checkpoint record")));
}
memcpy(&checkPoint, XLogRecGetData(xlogreader), sizeof(CheckPoint));
wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN);
wasShutdown = ((record->xl_info & ~XLR_INFO_MASK) == XLOG_CHECKPOINT_SHUTDOWN);
}
/*
@ -7785,6 +7786,7 @@ ReadCheckpointRecord(XLogReaderState *xlogreader, XLogRecPtr RecPtr,
int whichChkpt, bool report)
{
XLogRecord *record;
uint8 info;
if (!XRecOffIsValid(RecPtr))
{
@ -7810,6 +7812,7 @@ ReadCheckpointRecord(XLogReaderState *xlogreader, XLogRecPtr RecPtr,
}
record = ReadRecord(xlogreader, RecPtr, LOG, true);
info = record->xl_info & ~XLR_INFO_MASK;
if (record == NULL)
{
@ -7852,8 +7855,8 @@ ReadCheckpointRecord(XLogReaderState *xlogreader, XLogRecPtr RecPtr,
}
return NULL;
}
if (record->xl_info != XLOG_CHECKPOINT_SHUTDOWN &&
record->xl_info != XLOG_CHECKPOINT_ONLINE)
if (info != XLOG_CHECKPOINT_SHUTDOWN &&
info != XLOG_CHECKPOINT_ONLINE)
{
switch (whichChkpt)
{

3
src/backend/access/transam/xlogreader.c
View File

@ -462,7 +462,8 @@ XLogReadRecord(XLogReaderState *state, XLogRecPtr RecPtr, char **errormsg)
/*
* Special processing if it's an XLOG SWITCH record
*/
if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH)
if (record->xl_rmid == RM_XLOG_ID &&
(record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH)
{
/* Pretend it extends to end of segment */
state->EndRecPtr += XLogSegSize - 1;