From 58673b4a5fdff4d0d327c2d07e0cf8743f86f44c Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Sun, 5 Aug 2018 05:31:56 +0900 Subject: [PATCH] Reset properly errno before calling write() 6cb3372 enforces errno to ENOSPC when less bytes than what is expected have been written when it is unset, though it forgot to properly reset errno before doing a system call to write(), causing errno to potentially come from a previous system call. Reported-by: Tom Lane Author: Michael Paquier Reviewed-by: Tom Lane Discussion: https://postgr.es/m/31797.1533326676@sss.pgh.pa.us --- src/backend/access/heap/rewriteheap.c | 1 + src/backend/access/transam/twophase.c | 1 + src/backend/replication/logical/origin.c | 3 +++ src/backend/replication/logical/reorderbuffer.c | 1 + src/backend/replication/logical/snapbuild.c | 1 + src/backend/replication/slot.c | 1 + src/bin/pg_basebackup/walmethods.c | 6 ++++++ 7 files changed, 14 insertions(+) diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c index ed7ba181c79..85f92973c95 100644 --- a/src/backend/access/heap/rewriteheap.c +++ b/src/backend/access/heap/rewriteheap.c @@ -1166,6 +1166,7 @@ heap_xlog_logical_rewrite(XLogReaderState *r) len = xlrec->num_mappings * sizeof(LogicalRewriteMappingData); /* write out tail end of mapping file (again) */ + errno = 0; pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE); if (write(fd, data, len) != len) { diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index e8d4e37fe30..ed3e36c0c2a 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1665,6 +1665,7 @@ RecreateTwoPhaseFile(TransactionId xid, void *content, int len) path))); /* Write content and CRC */ + errno = 0; pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_WRITE); if (write(fd, content, len) != len) { diff --git a/src/backend/replication/logical/origin.c b/src/backend/replication/logical/origin.c index 595eb252d2a..46156ae6c6f 100644 --- a/src/backend/replication/logical/origin.c +++ b/src/backend/replication/logical/origin.c @@ -576,6 +576,7 @@ CheckPointReplicationOrigin(void) tmppath))); /* write magic */ + errno = 0; if ((write(tmpfd, &magic, sizeof(magic))) != sizeof(magic)) { int save_errno = errno; @@ -619,6 +620,7 @@ CheckPointReplicationOrigin(void) /* make sure we only write out a commit that's persistent */ XLogFlush(local_lsn); + errno = 0; if ((write(tmpfd, &disk_state, sizeof(disk_state))) != sizeof(disk_state)) { @@ -641,6 +643,7 @@ CheckPointReplicationOrigin(void) /* write out the CRC */ FIN_CRC32C(crc); + errno = 0; if ((write(tmpfd, &crc, sizeof(crc))) != sizeof(crc)) { int save_errno = errno; diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c index 9b55b94227b..1d43a165ad0 100644 --- a/src/backend/replication/logical/reorderbuffer.c +++ b/src/backend/replication/logical/reorderbuffer.c @@ -2421,6 +2421,7 @@ ReorderBufferSerializeChange(ReorderBuffer *rb, ReorderBufferTXN *txn, ondisk->size = sz; + errno = 0; pgstat_report_wait_start(WAIT_EVENT_REORDER_BUFFER_WRITE); if (write(fd, rb->outbuf, ondisk->size) != ondisk->size) { diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c index e975faeb8c9..ea454181946 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -1609,6 +1609,7 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn) ereport(ERROR, (errmsg("could not open file \"%s\": %m", path))); + errno = 0; pgstat_report_wait_start(WAIT_EVENT_SNAPBUILD_WRITE); if ((write(fd, ondisk, needed_length)) != needed_length) { diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index fb95b44ed82..94f7a99cfa4 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -1275,6 +1275,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel) SnapBuildOnDiskChecksummedSize); FIN_CRC32C(cp.checksum); + errno = 0; pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_WRITE); if ((write(fd, &cp, sizeof(cp))) != sizeof(cp)) { diff --git a/src/bin/pg_basebackup/walmethods.c b/src/bin/pg_basebackup/walmethods.c index fbfee05a5a6..42e3f3023a0 100644 --- a/src/bin/pg_basebackup/walmethods.c +++ b/src/bin/pg_basebackup/walmethods.c @@ -122,6 +122,7 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_ zerobuf = pg_malloc0(XLOG_BLCKSZ); for (bytes = 0; bytes < pad_to_size; bytes += XLOG_BLCKSZ) { + errno = 0; if (write(fd, zerobuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) { int save_errno = errno; @@ -445,6 +446,7 @@ tar_write_compressed_data(void *buf, size_t count, bool flush) { size_t len = ZLIB_OUT_SIZE - tar_data->zp->avail_out; + errno = 0; if (write(tar_data->fd, tar_data->zlibOut, len) != len) { /* @@ -629,6 +631,7 @@ tar_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_ if (!tar_data->compression) { + errno = 0; if (write(tar_data->fd, tar_data->currentfile->header, 512) != 512) { save_errno = errno; @@ -829,6 +832,7 @@ tar_close(Walfile f, WalCloseMethod method) return -1; if (!tar_data->compression) { + errno = 0; if (write(tar_data->fd, tf->header, 512) != 512) { /* if write didn't set errno, assume problem is no disk space */ @@ -901,6 +905,7 @@ tar_finish(void) MemSet(zerobuf, 0, sizeof(zerobuf)); if (!tar_data->compression) { + errno = 0; if (write(tar_data->fd, zerobuf, sizeof(zerobuf)) != sizeof(zerobuf)) { /* if write didn't set errno, assume problem is no disk space */ @@ -933,6 +938,7 @@ tar_finish(void) { size_t len = ZLIB_OUT_SIZE - tar_data->zp->avail_out; + errno = 0; if (write(tar_data->fd, tar_data->zlibOut, len) != len) { /*