Hi,
I am posting the new v2 patch, which is now rebased on the `master` branch.
Waiting for your feedback :)
--
Best regards,
Daniil Davydov
From 2e43a1411ebcb37b2c0c1d6bac758e48799d2c4e Mon Sep 17 00:00:00 2001
From: Daniil Davidov <d.davy...@postgrespro.ru>
Date: Tue, 11 Mar 2025 17:11:16 +0700
Subject: [PATCH v2] Add macros for safety access to smgr
---
src/backend/storage/buffer/bufmgr.c | 55 ++++++++++++---------------
src/backend/storage/buffer/localbuf.c | 10 +++--
src/include/storage/bufmgr.h | 14 +++++++
3 files changed, 45 insertions(+), 34 deletions(-)
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 7915ed624c1..c55228f298a 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -887,11 +887,8 @@ ExtendBufferedRelBy(BufferManagerRelation bmr,
Assert(bmr.smgr == NULL || bmr.relpersistence != 0);
Assert(extend_by > 0);
- if (bmr.smgr == NULL)
- {
- bmr.smgr = RelationGetSmgr(bmr.rel);
+ if (bmr.relpersistence == 0)
bmr.relpersistence = bmr.rel->rd_rel->relpersistence;
- }
return ExtendBufferedRelCommon(bmr, fork, strategy, flags,
extend_by, InvalidBlockNumber,
@@ -923,11 +920,8 @@ ExtendBufferedRelTo(BufferManagerRelation bmr,
Assert(bmr.smgr == NULL || bmr.relpersistence != 0);
Assert(extend_to != InvalidBlockNumber && extend_to > 0);
- if (bmr.smgr == NULL)
- {
- bmr.smgr = RelationGetSmgr(bmr.rel);
+ if (bmr.relpersistence == 0)
bmr.relpersistence = bmr.rel->rd_rel->relpersistence;
- }
/*
* If desired, create the file if it doesn't exist. If
@@ -935,15 +929,15 @@ ExtendBufferedRelTo(BufferManagerRelation bmr,
* an smgrexists call.
*/
if ((flags & EB_CREATE_FORK_IF_NEEDED) &&
- (bmr.smgr->smgr_cached_nblocks[fork] == 0 ||
- bmr.smgr->smgr_cached_nblocks[fork] == InvalidBlockNumber) &&
- !smgrexists(bmr.smgr, fork))
+ (BMR_GET_SMGR(bmr)->smgr_cached_nblocks[fork] == 0 ||
+ BMR_GET_SMGR(bmr)->smgr_cached_nblocks[fork] == InvalidBlockNumber) &&
+ !smgrexists(BMR_GET_SMGR(bmr), fork))
{
LockRelationForExtension(bmr.rel, ExclusiveLock);
/* recheck, fork might have been created concurrently */
- if (!smgrexists(bmr.smgr, fork))
- smgrcreate(bmr.smgr, fork, flags & EB_PERFORMING_RECOVERY);
+ if (!smgrexists(BMR_GET_SMGR(bmr), fork))
+ smgrcreate(BMR_GET_SMGR(bmr), fork, flags & EB_PERFORMING_RECOVERY);
UnlockRelationForExtension(bmr.rel, ExclusiveLock);
}
@@ -953,13 +947,13 @@ ExtendBufferedRelTo(BufferManagerRelation bmr,
* kernel.
*/
if (flags & EB_CLEAR_SIZE_CACHE)
- bmr.smgr->smgr_cached_nblocks[fork] = InvalidBlockNumber;
+ BMR_GET_SMGR(bmr)->smgr_cached_nblocks[fork] = InvalidBlockNumber;
/*
* Estimate how many pages we'll need to extend by. This avoids acquiring
* unnecessarily many victim buffers.
*/
- current_size = smgrnblocks(bmr.smgr, fork);
+ current_size = smgrnblocks(BMR_GET_SMGR(bmr), fork);
/*
* Since no-one else can be looking at the page contents yet, there is no
@@ -1003,7 +997,7 @@ ExtendBufferedRelTo(BufferManagerRelation bmr,
if (buffer == InvalidBuffer)
{
Assert(extended_by == 0);
- buffer = ReadBuffer_common(bmr.rel, bmr.smgr, bmr.relpersistence,
+ buffer = ReadBuffer_common(bmr.rel, BMR_GET_SMGR(bmr), bmr.relpersistence,
fork, extend_to - 1, mode, strategy);
}
@@ -2153,10 +2147,10 @@ ExtendBufferedRelCommon(BufferManagerRelation bmr,
BlockNumber first_block;
TRACE_POSTGRESQL_BUFFER_EXTEND_START(fork,
- bmr.smgr->smgr_rlocator.locator.spcOid,
- bmr.smgr->smgr_rlocator.locator.dbOid,
- bmr.smgr->smgr_rlocator.locator.relNumber,
- bmr.smgr->smgr_rlocator.backend,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.locator.spcOid,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.locator.dbOid,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.locator.relNumber,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.backend,
extend_by);
if (bmr.relpersistence == RELPERSISTENCE_TEMP)
@@ -2170,10 +2164,10 @@ ExtendBufferedRelCommon(BufferManagerRelation bmr,
*extended_by = extend_by;
TRACE_POSTGRESQL_BUFFER_EXTEND_DONE(fork,
- bmr.smgr->smgr_rlocator.locator.spcOid,
- bmr.smgr->smgr_rlocator.locator.dbOid,
- bmr.smgr->smgr_rlocator.locator.relNumber,
- bmr.smgr->smgr_rlocator.backend,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.locator.spcOid,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.locator.dbOid,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.locator.relNumber,
+ BMR_GET_SMGR(bmr)->smgr_rlocator.backend,
*extended_by,
first_block);
@@ -2239,9 +2233,9 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
* kernel.
*/
if (flags & EB_CLEAR_SIZE_CACHE)
- bmr.smgr->smgr_cached_nblocks[fork] = InvalidBlockNumber;
+ BMR_GET_SMGR(bmr)->smgr_cached_nblocks[fork] = InvalidBlockNumber;
- first_block = smgrnblocks(bmr.smgr, fork);
+ first_block = smgrnblocks(BMR_GET_SMGR(bmr), fork);
/*
* Now that we have the accurate relation size, check if the caller wants
@@ -2284,7 +2278,7 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("cannot extend relation %s beyond %u blocks",
- relpath(bmr.smgr->smgr_rlocator, fork).str,
+ relpath(BMR_GET_SMGR(bmr)->smgr_rlocator, fork).str,
MaxBlockNumber)));
/*
@@ -2306,7 +2300,8 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
ResourceOwnerEnlarge(CurrentResourceOwner);
ReservePrivateRefCountEntry();
- InitBufferTag(&tag, &bmr.smgr->smgr_rlocator.locator, fork, first_block + i);
+ InitBufferTag(&tag, &BMR_GET_SMGR(bmr)->smgr_rlocator.locator, fork,
+ first_block + i);
hash = BufTableHashCode(&tag);
partition_lock = BufMappingPartitionLock(hash);
@@ -2356,7 +2351,7 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
ereport(ERROR,
(errmsg("unexpected data beyond EOF in block %u of relation %s",
existing_hdr->tag.blockNum,
- relpath(bmr.smgr->smgr_rlocator, fork).str),
+ relpath(BMR_GET_SMGR(bmr)->smgr_rlocator, fork).str),
errhint("This has been seen to occur with buggy kernels; consider updating your system.")));
/*
@@ -2414,7 +2409,7 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
*
* We don't need to set checksum for all-zero pages.
*/
- smgrzeroextend(bmr.smgr, fork, first_block, extend_by, false);
+ smgrzeroextend(BMR_GET_SMGR(bmr), fork, first_block, extend_by, false);
/*
* Release the file-extension lock; it's now OK for someone else to extend
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 80b83444eb2..0b03920c17f 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -24,6 +24,7 @@
#include "utils/guc_hooks.h"
#include "utils/memutils.h"
#include "utils/resowner.h"
+#include "utils/rel.h"
/*#define LBDEBUG*/
@@ -341,7 +342,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
MemSet(buf_block, 0, BLCKSZ);
}
- first_block = smgrnblocks(bmr.smgr, fork);
+ first_block = smgrnblocks(BMR_GET_SMGR(bmr), fork);
if (extend_upto != InvalidBlockNumber)
{
@@ -360,7 +361,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("cannot extend relation %s beyond %u blocks",
- relpath(bmr.smgr->smgr_rlocator, fork).str,
+ relpath(BMR_GET_SMGR(bmr)->smgr_rlocator, fork).str,
MaxBlockNumber)));
for (uint32 i = 0; i < extend_by; i++)
@@ -377,7 +378,8 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
/* in case we need to pin an existing buffer below */
ResourceOwnerEnlarge(CurrentResourceOwner);
- InitBufferTag(&tag, &bmr.smgr->smgr_rlocator.locator, fork, first_block + i);
+ InitBufferTag(&tag, &BMR_GET_SMGR(bmr)->smgr_rlocator.locator, fork,
+ first_block + i);
hresult = (LocalBufferLookupEnt *)
hash_search(LocalBufHash, &tag, HASH_ENTER, &found);
@@ -417,7 +419,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
io_start = pgstat_prepare_io_time(track_io_timing);
/* actually extend relation */
- smgrzeroextend(bmr.smgr, fork, first_block, extend_by, false);
+ smgrzeroextend(BMR_GET_SMGR(bmr), fork, first_block, extend_by, false);
pgstat_count_io_op_time(IOOBJECT_TEMP_RELATION, IOCONTEXT_NORMAL, IOOP_EXTEND,
io_start, 1, extend_by * BLCKSZ);
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 7c1e4316dde..3f4228f88dc 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -100,13 +100,27 @@ typedef enum ExtendBufferedFlags
typedef struct BufferManagerRelation
{
Relation rel;
+
+ /*
+ * Must be accessed via BMR_GET_SMGR if we want to access some fields
+ * of structure
+ */
struct SMgrRelationData *smgr;
+
char relpersistence;
} BufferManagerRelation;
#define BMR_REL(p_rel) ((BufferManagerRelation){.rel = p_rel})
#define BMR_SMGR(p_smgr, p_relpersistence) ((BufferManagerRelation){.smgr = p_smgr, .relpersistence = p_relpersistence})
+/*
+ * In case of cache invalidation, we need to be sure that we access a valid
+ * smgr reference
+ */
+
+#define BMR_GET_SMGR(bmr) \
+ (RelationIsValid((bmr).rel) ? RelationGetSmgr((bmr).rel) : (bmr).smgr)
+
/* Zero out page if reading fails. */
#define READ_BUFFERS_ZERO_ON_ERROR (1 << 0)
/* Call smgrprefetch() if I/O necessary. */
--
2.43.0
