Fix buffile.c error handling.

Convert buffile.c error handling to use ereport.  This fixes cases where
I/O errors were indistinguishable from EOF or not reported.  Also remove
"%m" from error messages where errno would be bogus.  While we're
modifying those strings, add block numbers and short read byte counts
where appropriate.

Back-patch to all supported releases.

Reported-by: Amit Khandekar <amitdkhan.pg@gmail.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Ibrar Ahmed <ibrar.ahmad@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKGJE04G%3D8TLK0DLypT_27D9dR8F1RQgNp0jK6qR0tZGWOw%40mail.gmail.com

3 files changed, 47 insertions, 49 deletions

diff --git a/src/backend/utils/sort/logtape.c b/src/backend/utils/sort/logtape.c
index 2358c6fe523..50baf743a13 100644
--- a/src/backend/utils/sort/logtape.c
+++ b/src/backend/utils/sort/logtape.c
@@ -248,12 +248,12 @@ ltsWriteBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
 	}
 
 	/* Write the requested block */
-	if (BufFileSeekBlock(lts->pfile, blocknum) != 0 ||
-		BufFileWrite(lts->pfile, buffer, BLCKSZ) != BLCKSZ)
+	if (BufFileSeekBlock(lts->pfile, blocknum) != 0)
 		ereport(ERROR,
 				(errcode_for_file_access(),
-				 errmsg("could not write block %ld of temporary file: %m",
+				 errmsg("could not seek to block %ld of temporary file",
 						blocknum)));
+	BufFileWrite(lts->pfile, buffer, BLCKSZ);
 
 	/* Update nBlocksWritten, if we extended the file */
 	if (blocknum == lts->nBlocksWritten)
@@ -269,12 +269,19 @@ ltsWriteBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
 static void
 ltsReadBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
 {
-	if (BufFileSeekBlock(lts->pfile, blocknum) != 0 ||
-		BufFileRead(lts->pfile, buffer, BLCKSZ) != BLCKSZ)
+	size_t		nread;
+
+	if (BufFileSeekBlock(lts->pfile, blocknum) != 0)
 		ereport(ERROR,
 				(errcode_for_file_access(),
-				 errmsg("could not read block %ld of temporary file: %m",
+				 errmsg("could not seek to block %ld of temporary file",
 						blocknum)));
+	nread = BufFileRead(lts->pfile, buffer, BLCKSZ);
+	if (nread != BLCKSZ)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not read block %ld of temporary file: read only %zu of %zu bytes",
+						blocknum, nread, (size_t) BLCKSZ)));
 }
 
 /*
diff --git a/src/backend/utils/sort/sharedtuplestore.c b/src/backend/utils/sort/sharedtuplestore.c
index 265c04b3d39..d2555c2c3ba 100644
--- a/src/backend/utils/sort/sharedtuplestore.c
+++ b/src/backend/utils/sort/sharedtuplestore.c
@@ -198,14 +198,9 @@ static void
 sts_flush_chunk(SharedTuplestoreAccessor *accessor)
 {
 	size_t		size;
-	size_t		written;
 
 	size = STS_CHUNK_PAGES * BLCKSZ;
-	written = BufFileWrite(accessor->write_file, accessor->write_chunk, size);
-	if (written != size)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not write to temporary file: %m")));
+	BufFileWrite(accessor->write_file, accessor->write_chunk, size);
 	memset(accessor->write_chunk, 0, size);
 	accessor->write_pointer = &accessor->write_chunk->data[0];
 	accessor->sts->participants[accessor->participant].npages +=
@@ -557,6 +552,7 @@ sts_parallel_scan_next(SharedTuplestoreAccessor *accessor, void *meta_data)
 		if (!eof)
 		{
 			SharedTuplestoreChunk chunk_header;
+			size_t		nread;
 
 			/* Make sure we have the file open. */
 			if (accessor->read_file == NULL)
@@ -572,14 +568,15 @@ sts_parallel_scan_next(SharedTuplestoreAccessor *accessor, void *meta_data)
 			if (BufFileSeekBlock(accessor->read_file, read_page) != 0)
 				ereport(ERROR,
 						(errcode_for_file_access(),
-						 errmsg("could not read from shared tuplestore temporary file"),
-						 errdetail_internal("Could not seek to next block.")));
-			if (BufFileRead(accessor->read_file, &chunk_header,
-							STS_CHUNK_HEADER_SIZE) != STS_CHUNK_HEADER_SIZE)
+						 errmsg("could not seek block %u in shared tuplestore temporary file",
+								read_page)));
+			nread = BufFileRead(accessor->read_file, &chunk_header,
+								STS_CHUNK_HEADER_SIZE);
+			if (nread != STS_CHUNK_HEADER_SIZE)
 				ereport(ERROR,
 						(errcode_for_file_access(),
-						 errmsg("could not read from shared tuplestore temporary file"),
-						 errdetail_internal("Short read while reading chunk header.")));
+						 errmsg("could not read from shared tuplestore temporary file: read only %zu of %zu bytes",
+								nread, STS_CHUNK_HEADER_SIZE)));
 
 			/*
 			 * If this is an overflow chunk, we skip it and any following
diff --git a/src/backend/utils/sort/tuplestore.c b/src/backend/utils/sort/tuplestore.c
index 5560a3e1f6c..c24147a5c90 100644
--- a/src/backend/utils/sort/tuplestore.c
+++ b/src/backend/utils/sort/tuplestore.c
@@ -515,7 +515,7 @@ tuplestore_select_read_pointer(Tuplestorestate *state, int ptr)
 								SEEK_SET) != 0)
 					ereport(ERROR,
 							(errcode_for_file_access(),
-							 errmsg("could not seek in tuplestore temporary file: %m")));
+							 errmsg("could not seek in tuplestore temporary file")));
 			}
 			else
 			{
@@ -525,7 +525,7 @@ tuplestore_select_read_pointer(Tuplestorestate *state, int ptr)
 								SEEK_SET) != 0)
 					ereport(ERROR,
 							(errcode_for_file_access(),
-							 errmsg("could not seek in tuplestore temporary file: %m")));
+							 errmsg("could not seek in tuplestore temporary file")));
 			}
 			break;
 		default:
@@ -866,7 +866,7 @@ tuplestore_puttuple_common(Tuplestorestate *state, void *tuple)
 							SEEK_SET) != 0)
 				ereport(ERROR,
 						(errcode_for_file_access(),
-						 errmsg("could not seek in tuplestore temporary file: %m")));
+						 errmsg("could not seek in tuplestore temporary file")));
 			state->status = TSS_WRITEFILE;
 
 			/*
@@ -970,7 +970,7 @@ tuplestore_gettuple(Tuplestorestate *state, bool forward,
 								SEEK_SET) != 0)
 					ereport(ERROR,
 							(errcode_for_file_access(),
-							 errmsg("could not seek in tuplestore temporary file: %m")));
+							 errmsg("could not seek in tuplestore temporary file")));
 			state->status = TSS_READFILE;
 			/* FALLTHROUGH */
 
@@ -1034,7 +1034,7 @@ tuplestore_gettuple(Tuplestorestate *state, bool forward,
 									SEEK_CUR) != 0)
 						ereport(ERROR,
 								(errcode_for_file_access(),
-								 errmsg("could not seek in tuplestore temporary file: %m")));
+								 errmsg("could not seek in tuplestore temporary file")));
 					Assert(!state->truncated);
 					return NULL;
 				}
@@ -1051,7 +1051,7 @@ tuplestore_gettuple(Tuplestorestate *state, bool forward,
 							SEEK_CUR) != 0)
 				ereport(ERROR,
 						(errcode_for_file_access(),
-						 errmsg("could not seek in tuplestore temporary file: %m")));
+						 errmsg("could not seek in tuplestore temporary file")));
 			tup = READTUP(state, tuplen);
 			return tup;
 
@@ -1253,7 +1253,7 @@ tuplestore_rescan(Tuplestorestate *state)
 			if (BufFileSeek(state->myfile, 0, 0L, SEEK_SET) != 0)
 				ereport(ERROR,
 						(errcode_for_file_access(),
-						 errmsg("could not seek in tuplestore temporary file: %m")));
+						 errmsg("could not seek in tuplestore temporary file")));
 			break;
 		default:
 			elog(ERROR, "invalid tuplestore state");
@@ -1318,7 +1318,7 @@ tuplestore_copy_read_pointer(Tuplestorestate *state,
 									SEEK_SET) != 0)
 						ereport(ERROR,
 								(errcode_for_file_access(),
-								 errmsg("could not seek in tuplestore temporary file: %m")));
+								 errmsg("could not seek in tuplestore temporary file")));
 				}
 				else
 				{
@@ -1327,7 +1327,7 @@ tuplestore_copy_read_pointer(Tuplestorestate *state,
 									SEEK_SET) != 0)
 						ereport(ERROR,
 								(errcode_for_file_access(),
-								 errmsg("could not seek in tuplestore temporary file: %m")));
+								 errmsg("could not seek in tuplestore temporary file")));
 				}
 			}
 			else if (srcptr == state->activeptr)
@@ -1474,7 +1474,8 @@ getlen(Tuplestorestate *state, bool eofOK)
 	if (nbytes != 0 || !eofOK)
 		ereport(ERROR,
 				(errcode_for_file_access(),
-				 errmsg("could not read from tuplestore temporary file: %m")));
+				 errmsg("could not read from tuplestore temporary file: read only %zu of %zu bytes",
+						nbytes, sizeof(len))));
 	return 0;
 }
 
@@ -1511,22 +1512,10 @@ writetup_heap(Tuplestorestate *state, void *tup)
 	/* total on-disk footprint: */
 	unsigned int tuplen = tupbodylen + sizeof(int);
 
-	if (BufFileWrite(state->myfile, (void *) &tuplen,
-					 sizeof(tuplen)) != sizeof(tuplen))
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not write to tuplestore temporary file: %m")));
-	if (BufFileWrite(state->myfile, (void *) tupbody,
-					 tupbodylen) != (size_t) tupbodylen)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not write to tuplestore temporary file: %m")));
+	BufFileWrite(state->myfile, (void *) &tuplen, sizeof(tuplen));
+	BufFileWrite(state->myfile, (void *) tupbody, tupbodylen);
 	if (state->backward)		/* need trailing length word? */
-		if (BufFileWrite(state->myfile, (void *) &tuplen,
-						 sizeof(tuplen)) != sizeof(tuplen))
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not write to tuplestore temporary file: %m")));
+		BufFileWrite(state->myfile, (void *) &tuplen, sizeof(tuplen));
 
 	FREEMEM(state, GetMemoryChunkSpace(tuple));
 	heap_free_minimal_tuple(tuple);
@@ -1539,20 +1528,25 @@ readtup_heap(Tuplestorestate *state, unsigned int len)
 	unsigned int tuplen = tupbodylen + MINIMAL_TUPLE_DATA_OFFSET;
 	MinimalTuple tuple = (MinimalTuple) palloc(tuplen);
 	char	   *tupbody = (char *) tuple + MINIMAL_TUPLE_DATA_OFFSET;
+	size_t		nread;
 
 	USEMEM(state, GetMemoryChunkSpace(tuple));
 	/* read in the tuple proper */
 	tuple->t_len = tuplen;
-	if (BufFileRead(state->myfile, (void *) tupbody,
-					tupbodylen) != (size_t) tupbodylen)
+	nread = BufFileRead(state->myfile, (void *) tupbody, tupbodylen);
+	if (nread != (size_t) tupbodylen)
 		ereport(ERROR,
 				(errcode_for_file_access(),
-				 errmsg("could not read from tuplestore temporary file: %m")));
+				 errmsg("could not read from tuplestore temporary file: read only %zu of %zu bytes",
+						nread, (size_t) tupbodylen)));
 	if (state->backward)		/* need trailing length word? */
-		if (BufFileRead(state->myfile, (void *) &tuplen,
-						sizeof(tuplen)) != sizeof(tuplen))
+	{
+		nread = BufFileRead(state->myfile, (void *) &tuplen, sizeof(tuplen));
+		if (nread != sizeof(tuplen))
 			ereport(ERROR,
 					(errcode_for_file_access(),
-					 errmsg("could not read from tuplestore temporary file: %m")));
+					 errmsg("could not read from tuplestore temporary file: read only %zu of %zu bytes",
+							nread, sizeof(tuplen))));
+	}
 	return (void *) tuple;
 }