From 9989d37d1c8dff12f20a1de8e1f470093136c893 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Tue, 3 Dec 2019 15:06:04 +0900 Subject: [PATCH] Remove XLogFileNameP() from the tree MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit XLogFileNameP() is a wrapper routine able to build a palloc'd string for a WAL segment name, which is used for error string generation. There were several code paths where it gets called in a critical section, where memory allocation is not allowed. This results in triggering an assertion failure instead of generating the wanted error message. Another, more annoying, problem is that if the allocation to generate the WAL segment name fails on OOM, then the failure would be escalated to a PANIC. This removes the routine and all its callers are replaced with a logic using a fixed-size buffer. This way, all the existing mistakes are fixed and future ones are prevented. Author: Masahiko Sawada Reviewed-by: Michael Paquier, Álvaro Herrera Discussion: https://postgr.es/m/CA+fd4k5gC9H4uoWMLg9K_QfNrnkkdEw+-AFveob9YX7z8JnKTA@mail.gmail.com --- src/backend/access/transam/xlog.c | 90 +++++++++++++++++--------- src/backend/access/transam/xlogutils.c | 6 +- src/backend/replication/walreceiver.c | 30 ++++++--- src/backend/replication/walsender.c | 9 ++- src/include/access/xlog.h | 1 - src/include/access/xlog_internal.h | 4 ++ 6 files changed, 96 insertions(+), 44 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 5f0ee50092..ad08468420 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -2499,14 +2499,21 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible) pgstat_report_wait_end(); if (written <= 0) { + char xlogfname[MAXFNAMELEN]; + int save_errno; + if (errno == EINTR) continue; + + save_errno = errno; + XLogFileName(xlogfname, ThisTimeLineID, openLogSegNo, + wal_segment_size); + errno = save_errno; ereport(PANIC, (errcode_for_file_access(), errmsg("could not write to log file %s " "at offset %u, length %zu: %m", - XLogFileNameP(ThisTimeLineID, openLogSegNo), - startoffset, nleft))); + xlogfname, startoffset, nleft))); } nleft -= written; from += written; @@ -3792,10 +3799,17 @@ XLogFileClose(void) #endif if (close(openLogFile) != 0) + { + char xlogfname[MAXFNAMELEN]; + int save_errno = errno; + + XLogFileName(xlogfname, ThisTimeLineID, openLogSegNo, wal_segment_size); + errno = save_errno; ereport(PANIC, (errcode_for_file_access(), - errmsg("could not close file \"%s\": %m", - XLogFileNameP(ThisTimeLineID, openLogSegNo)))); + errmsg("could not close file \"%s\": %m", xlogfname))); + } + openLogFile = -1; } @@ -5510,10 +5524,17 @@ exitArchiveRecovery(TimeLineID endTLI, XLogRecPtr endOfLog) fd = XLogFileInit(startLogSegNo, &use_existent, true); if (close(fd) != 0) + { + char xlogfname[MAXFNAMELEN]; + int save_errno = errno; + + XLogFileName(xlogfname, ThisTimeLineID, openLogSegNo, + wal_segment_size); + errno = save_errno; ereport(ERROR, (errcode_for_file_access(), - errmsg("could not close file \"%s\": %m", - XLogFileNameP(ThisTimeLineID, startLogSegNo)))); + errmsg("could not close file \"%s\": %m", xlogfname))); + } } /* @@ -10079,10 +10100,19 @@ assign_xlog_sync_method(int new_sync_method, void *extra) { pgstat_report_wait_start(WAIT_EVENT_WAL_SYNC_METHOD_ASSIGN); if (pg_fsync(openLogFile) != 0) + { + char xlogfname[MAXFNAMELEN]; + int save_errno; + + save_errno = errno; + XLogFileName(xlogfname, ThisTimeLineID, openLogSegNo, + wal_segment_size); + errno = save_errno; ereport(PANIC, (errcode_for_file_access(), - errmsg("could not fsync file \"%s\": %m", - XLogFileNameP(ThisTimeLineID, openLogSegNo)))); + errmsg("could not fsync file \"%s\": %m", xlogfname))); + } + pgstat_report_wait_end(); if (get_sync_bit(sync_method) != get_sync_bit(new_sync_method)) XLogFileClose(); @@ -10100,32 +10130,25 @@ assign_xlog_sync_method(int new_sync_method, void *extra) void issue_xlog_fsync(int fd, XLogSegNo segno) { + char *msg = NULL; + pgstat_report_wait_start(WAIT_EVENT_WAL_SYNC); switch (sync_method) { case SYNC_METHOD_FSYNC: if (pg_fsync_no_writethrough(fd) != 0) - ereport(PANIC, - (errcode_for_file_access(), - errmsg("could not fsync file \"%s\": %m", - XLogFileNameP(ThisTimeLineID, segno)))); + msg = _("could not fsync file \"%s\": %m"); break; #ifdef HAVE_FSYNC_WRITETHROUGH case SYNC_METHOD_FSYNC_WRITETHROUGH: if (pg_fsync_writethrough(fd) != 0) - ereport(PANIC, - (errcode_for_file_access(), - errmsg("could not fsync write-through file \"%s\": %m", - XLogFileNameP(ThisTimeLineID, segno)))); + msg = _("could not fsync write-through file \"%s\": %m"); break; #endif #ifdef HAVE_FDATASYNC case SYNC_METHOD_FDATASYNC: if (pg_fdatasync(fd) != 0) - ereport(PANIC, - (errcode_for_file_access(), - errmsg("could not fdatasync file \"%s\": %m", - XLogFileNameP(ThisTimeLineID, segno)))); + msg = _("could not fdatasync file \"%s\": %m"); break; #endif case SYNC_METHOD_OPEN: @@ -10136,21 +10159,24 @@ issue_xlog_fsync(int fd, XLogSegNo segno) elog(PANIC, "unrecognized wal_sync_method: %d", sync_method); break; } + + /* PANIC if failed to fsync */ + if (msg) + { + char xlogfname[MAXFNAMELEN]; + int save_errno = errno; + + XLogFileName(xlogfname, ThisTimeLineID, openLogSegNo, + wal_segment_size); + errno = save_errno; + ereport(PANIC, + (errcode_for_file_access(), + errmsg(msg, xlogfname))); + } + pgstat_report_wait_end(); } -/* - * Return the filename of given log segment, as a palloc'd string. - */ -char * -XLogFileNameP(TimeLineID tli, XLogSegNo segno) -{ - char *result = palloc(MAXFNAMELEN); - - XLogFileName(result, tli, segno, wal_segment_size); - return result; -} - /* * do_pg_start_backup * diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 446760ed6e..14efbf37d6 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -776,7 +776,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa /* openSegment callback for WALRead */ static int -wal_segment_open(XLogSegNo nextSegNo, WALSegmentContext *segcxt, +wal_segment_open(XLogSegNo nextSegNo, WALSegmentContext * segcxt, TimeLineID *tli_p) { TimeLineID tli = *tli_p; @@ -944,7 +944,9 @@ void WALReadRaiseError(WALReadError *errinfo) { WALOpenSegment *seg = &errinfo->wre_seg; - char *fname = XLogFileNameP(seg->ws_tli, seg->ws_segno); + char fname[MAXFNAMELEN]; + + XLogFileName(fname, seg->ws_tli, seg->ws_segno, wal_segment_size); if (errinfo->wre_read < 0) { diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c index 72acb10767..c1e439adb4 100644 --- a/src/backend/replication/walreceiver.c +++ b/src/backend/replication/walreceiver.c @@ -576,17 +576,17 @@ WalReceiverMain(void) char xlogfname[MAXFNAMELEN]; XLogWalRcvFlush(false); + XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size); if (close(recvFile) != 0) ereport(PANIC, (errcode_for_file_access(), errmsg("could not close log segment %s: %m", - XLogFileNameP(recvFileTLI, recvSegNo)))); + xlogfname))); /* * Create .done file forcibly to prevent the streamed segment from * being archived later. */ - XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size); if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS) XLogArchiveForceDone(xlogfname); else @@ -900,6 +900,8 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr) XLogWalRcvFlush(false); + XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size); + /* * XLOG segment files will be re-read by recovery in startup * process soon, so we don't advise the OS to release cache @@ -909,13 +911,12 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr) ereport(PANIC, (errcode_for_file_access(), errmsg("could not close log segment %s: %m", - XLogFileNameP(recvFileTLI, recvSegNo)))); + xlogfname))); /* * Create .done file forcibly to prevent the streamed segment * from being archived later. */ - XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size); if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS) XLogArchiveForceDone(xlogfname); else @@ -943,11 +944,18 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr) if (recvOff != startoff) { if (lseek(recvFile, (off_t) startoff, SEEK_SET) < 0) + { + char xlogfname[MAXFNAMELEN]; + int save_errno = errno; + + XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size); + errno = save_errno; ereport(PANIC, (errcode_for_file_access(), errmsg("could not seek in log segment %s to offset %u: %m", - XLogFileNameP(recvFileTLI, recvSegNo), - startoff))); + xlogfname, startoff))); + } + recvOff = startoff; } @@ -957,15 +965,21 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr) byteswritten = write(recvFile, buf, segbytes); if (byteswritten <= 0) { + char xlogfname[MAXFNAMELEN]; + int save_errno; + /* if write didn't set errno, assume no disk space */ if (errno == 0) errno = ENOSPC; + + save_errno = errno; + XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size); + errno = save_errno; ereport(PANIC, (errcode_for_file_access(), errmsg("could not write to log segment %s " "at offset %u, length %lu: %m", - XLogFileNameP(recvFileTLI, recvSegNo), - recvOff, (unsigned long) segbytes))); + xlogfname, recvOff, (unsigned long) segbytes))); } /* Update state for write */ diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 8bafa65e50..8b2a2be1c0 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -2434,10 +2434,17 @@ WalSndSegmentOpen(XLogSegNo nextSegNo, WALSegmentContext *segcxt, * too old WAL segment that has already been removed or recycled. */ if (errno == ENOENT) + { + char xlogfname[MAXFNAMELEN]; + int save_errno = errno; + + XLogFileName(xlogfname, *tli_p, nextSegNo, wal_segment_size); + errno = save_errno; ereport(ERROR, (errcode_for_file_access(), errmsg("requested WAL segment %s has already been removed", - XLogFileNameP(*tli_p, nextSegNo)))); + xlogfname))); + } else ereport(ERROR, (errcode_for_file_access(), diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h index d519252aad..9b588c87a5 100644 --- a/src/include/access/xlog.h +++ b/src/include/access/xlog.h @@ -288,7 +288,6 @@ extern bool RecoveryIsPaused(void); extern void SetRecoveryPause(bool recoveryPause); extern TimestampTz GetLatestXTime(void); extern TimestampTz GetCurrentChunkReplayStartTime(void); -extern char *XLogFileNameP(TimeLineID tli, XLogSegNo segno); extern void UpdateControlFile(void); extern uint64 GetSystemIdentifier(void); diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h index e7e10beb4c..e295dc65fb 100644 --- a/src/include/access/xlog_internal.h +++ b/src/include/access/xlog_internal.h @@ -152,6 +152,10 @@ typedef XLogLongPageHeaderData *XLogLongPageHeader; /* Length of XLog file name */ #define XLOG_FNAME_LEN 24 +/* + * Generate a WAL segment file name. Do not use this macro in a helper + * function allocating the result generated. + */ #define XLogFileName(fname, tli, logSegNo, wal_segsz_bytes) \ snprintf(fname, MAXFNAMELEN, "%08X%08X%08X", tli, \ (uint32) ((logSegNo) / XLogSegmentsPerXLogId(wal_segsz_bytes)), \