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0d9114b704
pgaio_io_reclaim() reset the fields in PgAioHandle before updating the state to IDLE or incrementing the generation. For most things that's OK, but for pg_get_aios() it is not - if it copied the PgAioHandle while fields were being reset, we wouldn't detect that and could call pgaio_io_get_target_description() with ioh->target == PGAIO_TID_INVALID, leading to a crash. Fix this issue by incrementing the generation and state earlier, before resetting. Also add an assertion to pgaio_io_get_target_description() for the target to be valid - that'd have made this case a bit easier to debug. While at it, add/update a few related assertions. Author: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/062daca9-dfad-4750-9da8-b13388301ad9@gmail.com
123 lines
3.2 KiB
C
123 lines
3.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* aio_target.c
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* AIO - Functionality related to executing IO for different targets
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*
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* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* src/backend/storage/aio/aio_target.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "storage/aio.h"
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#include "storage/aio_internal.h"
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#include "storage/smgr.h"
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/*
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* Registry for entities that can be the target of AIO.
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*/
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static const PgAioTargetInfo *pgaio_target_info[] = {
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[PGAIO_TID_INVALID] = &(PgAioTargetInfo) {
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.name = "invalid",
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},
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[PGAIO_TID_SMGR] = &aio_smgr_target_info,
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};
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/* --------------------------------------------------------------------------------
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* Public target related functions operating on IO Handles
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* --------------------------------------------------------------------------------
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*/
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bool
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pgaio_io_has_target(PgAioHandle *ioh)
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{
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return ioh->target != PGAIO_TID_INVALID;
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}
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/*
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* Return the name for the target associated with the IO. Mostly useful for
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* debugging/logging.
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*/
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const char *
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pgaio_io_get_target_name(PgAioHandle *ioh)
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{
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/* explicitly allow INVALID here, function used by debug messages */
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Assert(ioh->target >= PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT);
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return pgaio_target_info[ioh->target]->name;
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}
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/*
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* Assign a target to the IO.
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*
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* This has to be called exactly once before pgaio_io_start_*() is called.
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*/
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void
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pgaio_io_set_target(PgAioHandle *ioh, PgAioTargetID targetid)
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{
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Assert(ioh->state == PGAIO_HS_HANDED_OUT);
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Assert(ioh->target == PGAIO_TID_INVALID);
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ioh->target = targetid;
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}
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PgAioTargetData *
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pgaio_io_get_target_data(PgAioHandle *ioh)
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{
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return &ioh->target_data;
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}
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/*
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* Return a stringified description of the IO's target.
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*
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* The string is localized and allocated in the current memory context.
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*/
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char *
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pgaio_io_get_target_description(PgAioHandle *ioh)
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{
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/* disallow INVALID, there wouldn't be a description */
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Assert(ioh->target > PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT);
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return pgaio_target_info[ioh->target]->describe_identity(&ioh->target_data);
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}
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/* --------------------------------------------------------------------------------
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* Internal target related functions operating on IO Handles
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* --------------------------------------------------------------------------------
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*/
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/*
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* Internal: Check if pgaio_io_reopen() is available for the IO.
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*/
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bool
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pgaio_io_can_reopen(PgAioHandle *ioh)
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{
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Assert(ioh->target > PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT);
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return pgaio_target_info[ioh->target]->reopen != NULL;
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}
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/*
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* Internal: Before executing an IO outside of the context of the process the
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* IO has been staged in, the file descriptor has to be reopened - any FD
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* referenced in the IO itself, won't be valid in the separate process.
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*/
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void
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pgaio_io_reopen(PgAioHandle *ioh)
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{
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Assert(ioh->target > PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT);
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Assert(ioh->op > PGAIO_OP_INVALID && ioh->op < PGAIO_OP_COUNT);
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pgaio_target_info[ioh->target]->reopen(ioh);
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}
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